Using "like" on your varchar (or lztext) contents is the only way, at the moment. Be patient, solving this problem is near the top of the list for the OpenACS project.
The problem for web work is that solutions that depend entirely on the database for building and containing an index for searching tend to be slow, complex, and troublesome. Oracle's InterMedia, for instance. Photo.net's not automatically indexed at this point, but rather is done by hand every couple of weeks, because of InterMedia problems.
There is something out there called PLS, which is also owned by AOL. It builds indices on its own for searching. Since these can easily be reconstructed from the database, there's really no need for search indices to be maintained in the database. PLS has the reputation of being very fast and very good.
It's not open source and not supported under Linux, at the moment. There is some hope that AOL might open source it. If not, we need to search for another solution.
