Using SQLite in Mac App
Depending on your data needs you might consider using Core Data. It's not right for every situation, but it might be a good thing to check out. It can store data in XML, sqlite formats on the backend, so you can pick the right format depending on the data characteristics of your app.
If you know you want SQLite directly, FMDB is a good wrapper around it. I used FMDB a few years ago in a Mac app for a client and it worked pretty well.
Even if FMDB isn't your style reading the source may give you a good example of how the sqlite API works.