I had this problem and it started complaining that my iTunes billing info had changed and kept telling me to visit the iTunes store on my computer every time I tried to download an app. I refreshed my billing info, uninstalled all my apps, restarted the phone and now it works fine.
hey im actually having a issue similar to this. but its with the mail program. i try to start it up and and it seems like its loading but then it just goes back to the springboard. i've tried turning it off and leaving it off for a while and turning it back on....but its still doing it. not sure what my other option is besides a restore?