For those of you who find it very cumbersome to search through the RoR APIs (Ctrl + F in Firefox anybody?) check out this search engine I put together at http://www.rorapi.com/. I put this together so it just crawls the Rails, Ruby Core, and Ruby Standard Library API (no blogs to clutter it up). I've also included a Firefox search plugin... I hope this helps!
Just tried a search and in Firefox 2.0 I get no results and an error on line 3 of gstats.js "missing ; before statement"
Works in IE7 though.