My speed on the iPhone is pretty fair, but not fast enough to watch videos and such seamlessly. Guess it's just my area, what speed should it get normally?
The internet speed depends upon a lot of factors and on most cases it depends mainly on the cellular signal accessibility. With the support for 7.2Mbps HSDPA, iPhone 3G, you can access internet at a much faster rate but you have to check your signal strength and accessibility in your location.
I get a speed above 2mbps. It works properly for me. And as said, you will have to check the disturbances and power of signals. It the place is too messy, you will not get proper connection.