
It's hard to tell from the pictures, but the NuTouch has a front panel that totally covers the iPhone's touchscreen, while leaving holes for the phone speaker and the Home button. The back panel slides onto it with a plastic latch, and there are openings for the camera, dock connector (we couldn't dock while the case was on, though), and the volume, Silent, and Sleep controls.
The thin plastic film that the case uses over the touchscreen does allow you to control the iPhone through it, but you will find yourself needing to press a little bit harder than you would normally. (Builds the finger strength, don'tcha know? But it can be a pain if you do a lot of iPhone gaming.) The main problem we had with it was that the opening for the Home button felt a little deep. The edges of it rubbed against our thumb each time we pushed it, which got annoying after about 2 minutes -- and never got un-annoying.
Links:
[1] http://www.maclife.com/user/sochs
[2] http://www.maclife.com/article/reviews/fommycom_nutouch_case_iphone_3g
[3] http://www.maclife.com/iphone3gcases
[4] http://www.maclife.com/article/reviews/scosche_kickback
[5] http://www.maclife.com/article/reviews/incase_slider_case_iphone_3g_0
[6] http://www.fommy.com/view-full-page.asp?divid=Apple&model=iPhone 3G&skuno=81344