3G iphone screen becomes unresponsive

whats up guys and gals..
ive had my iPhone for a good month and a half now and i gotta say i love it. i havent had any major problems with it. the one and only true complaint i have about it is .... my screen gets unresponsive numerous times in a day. i usually end up force quitting the app, or i would just lock it, and unlock it... and it gets back to normal.
all i did to the iphone was install 5 games, google earth, aim, pandora and shazam.. well, ive got like numerous ringtones as well. but nothing too crazy on it. as far as songs on it for use as an ipod, i dont have any.
i just dont know how to fix this problem... screen all unresponsive at times. is my iphone crashing from time to time? do i have a software glitch? i dont know what to do!?
any advice would prove helpful...! oh yeah, i have version 2.2.1..? i think thats the latest software thats out right now... seeing that i just got this phone like 2months ago. hehe.
please help! thanks!
hp Windows XP