I can't find a place to check my iPhone version.
Follow these steps:
1. Tap the 'Settings' icon.
2. Tap 'General'
3. Tap 'About' and you will see the version info of your iPhone.
they are all ez to tell appart except the 3g and 3gs but if you look at the lettering on the back of the 3gs it will be silver (just like the apple icon) compaired to the 3g will be grey