my iphone 3g in boot loop after sync with itunes HELP

Today I synced my iphone to my windows 7 with the latest version of itunes. Last ngiht I donwloaded GT Racing Academy Free+ but it didnt show up on my home screen, so i synced it today so that i could take it off, i succcesfully got it to work but before the sync could finish, my phone turned off and now its in a loop. I didn't even get to the Apple Logo. Please HELP!!!!