Scott Anguish, who started the excellent Stepwise website back in the NeXT days, and who is now one of the main list moderators for the Cocoa-Dev mailing list (and also currently works for Apple), has recently started a blog.
There's not much there yet, but one of his recent postings includes a sample Xcode project created showing some cool Core Animation stuff. It's a Mac application, not an iPhone one, but it's small, really clean, and well-written example of Core Animation code. Though there are some differences between using CA on the Mac and iPhone, there are enough similarities to make it well worth your while to download the project and read through the code. Scott was an old hand at Objective-C when I started learning it toward the end of the last millennia.
Here is the blog posting with the link to the project.