two months ago I upgraded my IOS from 3.1.3 to 4.00. Two problems, one of which I need to solve. The first problem is the slowness. To solve this if you jailbreak is to install backgrounder and in the seetings disable multitasking. I don't need it that much. I don't play that many video games. So I don't miss the multitasking. The second one is the Wifi. Wifi doesn't work. I can search for a Wifi. When a connect it appears to connect but then it disconnects automatically. I have reset network settings and have even reset all settings and still have the same problem. I can connect to any wifi just fine but within seconds it disconnects without any warns. Even when I disable the 3G connect the Wifi disconnects. I have been bearing with this but now there is a wifi in my area I have access to.