BIT-101
http://www.bit-101.com/blog/
BIT-101 used to talk a lot about Actionscript, but recently has been learning Objective-C and the iPhone. Since I am in a similar boat, I find the way he thinks about programming easier to understand that other writers. Often posts user tutorials and code snippets. 

PReV
http://bill.dudney.net/roller/objc/
Written by Bill Dudney, author of a couple good books about iPhone development.

Jeff Lamarche
http://iphonedevelopment.blogspot.com/ 
Turned me on to the wonderful and beautiful Accessorizer.

Cocoa With Love
http://cocoawithlove.com/
You’d probably want to know a few things about Cocoa & objective-c before looking at this blog…they’re pretty heady…and really good.

iPhone Developer Tips
http://iphonedevelopertips.com/
More a repository of code snippets than a blog. I have come across a couple useful tips here that answered problems that had been annoying me.

App Craver
http://www.appcraver.com 
Posts reviews and descriptions of new apps coming to the Apple App Store. Good resource to thumb through and see what other people are doing out there. Not all the apps they post are stellar, but knowing what doesn’t work is just as important as what does.