All My 3rd Party Apps Quit Instantly

Last night I synced my iPhone 3G so I could swap out music in preparation for a trip.

Now none of my apps work except the ones that came preinstalled. Anything I try starts to launch, shows its start screen, then immediately quits.

IPod, maps, email, calendar, etc. all work fine.

I thought I might try reinstalling, but when I opened the app store app it said the app store was not available.

Now I'm away from home with no computer. What can I do?

Yup, I rebooted twice. I discovered the problem just before leaving to catch my bus, so I synced it again, too, but that didn't work either.

I can't connect to the app store. Maybe it's the bus wifi or maybe it's something else. I'll try again when I get to my destination.