One of the hottest trends on the PC desktop--and a very relevant one for office users of PDF documents, which pretty much all of us are--is the spate of PC desktop search tools that have been released, and are under development for future “Longhorn” versions of the Windows operating system.

These nifty little utilities index all your files, return much faster results than the search feature Microsoft gives you with Windows, and best of all, the indices update themselves while you’re away from your machine.

One of the large players in this arena is the popular Web search engine Google, which recently introduced a beta of its free desktop search tool. One big problem? It will index things such as Microsoft Office documents and AOL instant message transcripts, but it won’t index PDFs. However, there’s hope: Google pledges to add more formats in future versions, and offers users a place to ask for them.

“Google Desktop Search is still under development as a beta product,” the company says at its “About Google Desktop Search” page. We intend to add new file, e-mail, and chat formats and browsers as Google Desktop Search evolves, and when new formats are created and used. If there's a format you'd like Google Desktop Search to be able to search, please let us know. We can't guarantee that we'll add every type that's suggested, but your suggestions will let us know what formats are important to you.”