ill look around, but one cool 'talk to make it do shit' app i have on my iphone 4, is google search. its free in the app store, has a blue logo with a white cursive G. you can say anything and it searches it, and it also has a feature called google goggles. google goggles lets you take a picture of anything, and search on google based on the picture you took.
a program called mobile mouse is nice if you use your computer on your television, or just want a multi purpose wifi based mouse/keyboard...very functional, has a free download for windows, mac, or linux. and I believe a free version of the app in the app store.
and the netflix app. its a free app, and if you dont already have netflix, the free 1 month trial is worth it! you can watch alot of tv shows/movies on the go...very handy.