Interesting. I know that the App always crash on 4.2.1. Maybe this is related.
What iOS version do you have? Do you know if bitcoin has a recovery command-line-flag I can use?
4.2.1, which I gather is the last for iPhone 3G. Works fine on an iPod Touch running 4.3 though. Probably should just prevent installs on 3G/4.2.1.