I used objective-c activerecord in IttyBooks as my ORM layer.
I fixed some bugs and made some API changes. Most of the API changes where for performance or memory reasons. While activerecord is not as feature complete as its Ruby cousin, it was nice to contribute. Sure beats mixing SQL in objective-c as well.
Anyway, you can view all of my changes on my fork at github. And they should end up merged back in aptiva’s master tree as well.
Gota love github!