You can still browse the internet on just the network its just allot slower. like a step down from dial-up.
You cant stream most music("xiialite" streams at 24kbps but it cuts off sometimes after a couple of minutes and has to buffer)
No video without wifi. (I have youtube vids, movies, and music saved on my sd card.)
Just gotta find little ways around having a slower network when your on the go. the apps in the ANDROID market are very helpul. but to answer your original question yes but its utilized best when just using it to read articles and posting in forums and what not.
Also phone comes with two browsers ANDROID webkit browser best used with wifi. and the Opera Mini 5 browser this should be your preferred browser when not on wifi connection.
settings> applications> browsers> either choose to have it as your default or not.
(when you dont you can still access opera from the red "O" graphic in pull up screen and ANDROID browser by clicking the "world" graphic.)