Denis, here's an excellent tutorial on ACS Service Contracts (includes info about search) by Benjamin:
http://vrusp.com/intro-to-service-contracts.htmlFor more info about OpenFTS check out http://openfts.sourceforge.net/
Note that OpenFTS is based on tsearch (a postgresql module) which has recently changed, heavily. Feel free to check out the new docs from the CVS tree (not yet released -- due next couple of weeks).