You can jailbreak your iPhone 4 and iPad running iOS 5.0.1. Just know that you cannot yet jailbreak dualcore devices, so the iPhone 4S and iPad 2 are out of the question. The other thing to keep in mind is that you will have to run it as a tethered jailbreak. At best, maybe semi-tethered, which at least gives you the ability to reboot your phone, but without jb apps.
Here are our links to the jailbreak tools you need. Feel free to bookmark the following page:
Just in case you want easy access to firmware files: