Yeah, Beginning iPhone Development is a great book. I've bought 2 other books since I picked that one up ("iPhone SDK Programming" by Maher Ali and "The iPhone Developer's Cookbook" by Erica Sadun) and the Mark & LaMarche book is the one I refer to most frequently.
The Sadun book is pretty good as well - shows some other tricks that the Beginning iPhone Development book kinda glosses over (nothing significant though; mostly just extra features on controls and even a few undocumented API's which might get you in a bit of trouble!)
I'd also recommend you check out this website for some video tutorials; I find anything by Zack Carter (zcarter) to be pretty informative and useful:
Welcome to the iPhone Development Central Website!
Dave
