At Locayta we have released a beta of our new full text search engine library for iPhone/iPad developers. I have been leading this project from the software engineering side and am looking for developers interested in beta testing this framework and offering some feedback.
To download the beta version, go to http://www.locayta.com/pages/new/ios-search-engine
Here is a quick blurb about the search engine library:
Locayta Seach for iOS is a port of Locayta's full text search engine library for the iOS platform. The core library is pure C (with a bit of C++) and we have wrapped a higher level Objective-C API around it and produced a static library in a Framework bundle so that iPhone & iPad apps can provide fast local full text search. The search engine provides "enterprise level" full text search using a probabilistic model of document terms, along with clever features to improve search success such as automatic spell correction (based on trigram analysis of terms) and word stemming.