Iphone Loopt hangs when signing in

Loopt on Iphone 3GS keeps spinning/draining battery indefinately. Even on wifi sometimes. On old 3G it would only connect 5-10 seconds, then stop spinning. Seems to have something to do with 3.0 software. My friends with Iphones report same problem. I've tried deleting and reinstalling. Only works the first signin, then starts hanging again.