When I was out trying infrared photography with my iPhone 3Gs I really lusted after a tripod. And now it is here. The people at Joby who make the bendy GorillaPod have made one for the iPhone called the Joby Gorillamobile for 3Gs.
This A$59 recommended retail price in Australia tripod comes with a case for the iPhone that includes the coupling to the tripod, making it easy to attach and detach your phone from the tripod. It also comes with two adhesive pads for attachment to other devices as well as a a tripod screw attachment.
Joby also provide a free self-timer app for the iPhone with a selectable delay, grid screen and more.
For those in the US it is also available from Amazon.