While the iPhone 3GS got a download speed boost—to 7.2Mbps—it didn't get any upload power-up. According to PC World, its upstream speed is limited by its hardware to 384Kbps. But don't get out the torches and pitchforks yet.
Most GSM-based cellphones suffer the same problem: No matter how fast they are at download, they will upload at only 384Kbps, or less, as you can see in our iPhone 3GS network test. This is because the hardware doesn't support the HSUPA (High-Speed Uplink Packet Access) standard, created by Nokia—the 3rd Generation Partnership Project (3GPP) refers to this standard as Enhanced Uplink.
Some would say that this is not needed because Enhanced Uplink—which runs at 1.4 and 1.9Mbps—is not supported by AT&T yet, but in Europe there are networks that already support this standard. I would imagine that users of the popular JesusPhone would love to upload their photos and videos to Facebook and YouTube as fast as possible.
On the other side, with AT&T still struggling to get 7.2Mbps off the ground and most of the other networks having problems and slowdowns everywhere, I would be happy if they all just managed to actually deliver their advertised download speeds.