I took a picture yesterday and since my camera app won't open. Anyone know how to fix this problem?
Try going into settings -> Applications -> Manage applications. Find your camera app and clear data. If all else fails, factory reset the phone. If it's still broken, exchange the phone for a new one.
Did you try restarting the phone? The camera app is probably just hung up. I'd reboot before I tried anything listed above. Alternately, you could find the camera app, but instead of clearing data just force stop the camera app.
This is just a stab in the dark here but do you have a flashlight app installed on your phone? The only reason I ask is because I was looking for a flashlight similar to the one that came with Froyo. I downloaded and installed 2 or 3 and they both kept the camera app from loading. I uninstalled them and, problem solved.