The challenge of finding a good enterprise search engine is already considerable. With the amount of data held on file in corporate databases approximately doubling every two years, the battle is on to find ever more precise searches to cut through the clutter.

At the same time, search capabilities are beginning to be extended to an ever-wider range of information, from database entries and e-mail to images, voice mail, music and video clips.

Now add to this the idea that these searches need to be available over the mobile phones and personal digital assistants that companies are increasingly looking to use for accessing the corporate back office.

Suddenly, all the problems multiply a hundred fold. Long lists of search results - frustrating enough to scroll through on a PC monitor, become completely unworkable on the tiny screens of wireless devices. Downloading pages to view results becomes a nightmare on limited bandwidth and unstable wireless connections. Typing in precise search terms is an exercise in patience with a mobile number pad or PDA stylus.

Considering the magnitude of the problem, surprisingly little is happening on the development front. Much of this is a reflection of the slowing economy, which has put a tight reign on corporate IT spending. Companies are interested in integrating mobile devices into the workplace, but their plans tend to be fairly limited, focusing on simple e-mail and calendar functions, rather than more complex data processing.

"Most IT managers are considering providing e-mail on a mobile basis," say Diego MacKee, marketing manager at Nextra, the Swedish mobile infrastructure company. "But when it comes to more complex functions the interest goes down dramatically."

Some search software companies, such as Verity and Inktomi, freely admit that plans for many of the wireless products they were thinking about a year ago are now either on hold or scrapped altogether because of lack of demand.

Others, such as Autonomy and iPhrase, have brought out wireless products, but are having trouble finding a market. "If I were them I would put this technology in the cellar and take it out in three years," says Alexander Linden, analyst at Gartner Dataquest.

Where companies do put wireless search technology in place, software changes tend to be small and incremental, often involving a simple adaptation of existing systems. Oracle, Siebel and SAP databases already have features that allow wireless connections and many companies simply patch these into their wireless networks. The demand for a more universal, out-of-the box mobile search technology is very small.

"In five to ten years time you could have something generic, but at the moment everything has to provide high return on investment and therefore needs to be tightly modified," says David Rice, managing director of AvantGo, the UK-based wireless software company.

One of the developments coming on slower than expected is the use of voice recognition for searching. On the one hand voice commands are seen as an obvious way to overcome the limitations of the small screen and keypad or stylus, and simple voice and text integration - having e-mails read out over the phone for example - is already in use to a limited extent.

Software companies such as Comverse, keen to capture a share of the future voice portal market, are now working on the next level of complexity, which could one day lead to a voice-activated search.

But, admits Michael Krasner, vice president and general manager for Comverse's voice solutions unit, demand is unlikely to gain momentum until the industry finally makes the long-hyped move to higher data capacity third-generation mobile networks and handsets that can process both voice and data at the same time. In the meantime, he admits, obsession with return on investment is making companies reluctant to try the technology out.

"A year ago the telecommunications industry was growing so fast companies invested in things more on faith. Today, things have moved back down to earth. People are saying 'Show me the business case'," he says.

While voice is waiting for momentum, a few drips and drabs of development are coming through. For example, wireless software companies AvantGo and Pumatech, which approach the issue from a mobile rather than search specialist perspective, have begun evolving the concept of search into a mobile alert service.

Instead of users typing in search requests ad hoc, they have developed search software that automatically looks for information at certain intervals, according to a set of previously set-up preferences, and sends text alerts to the user. A company's sales representative in the south east of the UK, for example, might receive news updates about his particular set of clients and messages about changes in a product database or a warehouse inventory.

"In the mobile environment there is still a need for search, but the focus is more on getting just the relevant information in real time," says Kevin Vine, managing director of Pumatech's European operations.

Convera, the company that provides corporate search engines for the likes of Nasa and the World Bank, meanwhile, has tapped into the fad for wireless e-mail by creating search software that piggy backs on this system. Search queries are e-mailed to central corporate search engine and the results are returned as e-mail attachments.

Xerox, the copier company, has also launched software that allow search results to be sent to an e-mail address or printed out on a fax machine. The search still needs to take place over an unsteady wireless connection, but at least the problems of viewing the received material are eased.

On a smaller scale, a US start-up called Survol is an indicator that at least some "created-in-a-garage"-type developments are happening in this area. Survol has sought to ease the difficulties or viewing search results by developing a way of putting lists of found documents into a flowchart that is seamlessly streamed onto the screen. Scrolling through the list requires no further time consuming downloads and is easy to navigate simply by using the up, down, left and right arrow keys of a mobile or PDA.

The trouble with these solutions, large or small, however, is that there is still little proven take-up. The software is generally in a beta test phase or, at best, in a soft launch that involves a few clients.

Survol may, in fact, be an interesting test case. The company is in talks with a number of mobile equipment makers and network operators, which could see the technology integrated into wireless hardware or a mobile portal. Despite the cautious climate it hopes to finalise a deal before the end of the year. If it does, it could be a sign of reviving confidence in this niche sector. For the moment, however, all the indications are that the search for wireless search investors could be a very frustrating search indeed.