On the php|architect site there's a recent tutorial from Jeremy Kendall about full-text searching in SQLite, a lightweight database alternative that, since it's stored locally, can be used without a full database server.

Full-text search with SQLite is so ridiculously easy to implement, there are only two valid reasons you haven't done it yet. The first is you don't need the full-text capability, and the second is you didn't know it could be done.

In his method he creates a full-text search table (using fts4) and populating it with your data. You can use the "MATCH" keyword in your SQL to find the closest matches and even handy modifiers like "NEARBY", wildcards and token/prefixes in queries. For more detailed information, check out the SQLite documentation for a full guide.