Update 1: iOS 5 Final version has been released for Download and Jailbreak - Click Here
Here's another trick has been spotted by the guys over CultofMac in the newly Apple's iOS 5 beta 1. You will be able to download and install more than one app at the same time, even on 3G.
In iOS 5's predecessors you were only able to download only one app at a time. In case you wanted to download another app, you will get a "Waiting..." message until the first app finished downloading.