One the mere look one can go for Toshiba TG01,because it has a slim look and a wide screen with REGZA technology.its thickness is only 9.9mm while iPhone 3G S is 12.3 mm  also while comparing the weight its lighter than iPhone 3G S.The weight of TG01 is 129g while that of 3G S is 135g.TG01 has a camera with a resolution of 3.2 MP while 3G S has a camera of 3.0 MP but both doesn't have the flash.Though 3G S has the latest processor which is twice as fast as 3G its quiet slower than TG01 since TG01 has a 256 MB RAM embedded with it.

3GS takes advantage in memory.It has a 32GB memory while TG01 has 16 GB only.

Comparing the battery TG01 uses li-ion battery which can be replacable but 3GS 's battery cannot be replaceble but apple improved its life compared to that of 3G

Apple's 3.0 frame work makes everything easy to work and its user friendly even to the disabled ppl.While TG uses Windows mobile OS which is comparitively not User friendly.

remaining features are almost same in both.So now you could decide to buy a user friendly mobile with enourmous space or a mobile with fashion and speed.:)