Pod2g, The hacker who is known for his iOS 5.0.1 jailbreak and the main person behind the up coming 5.1.1 jailbreak posted on his blog the list of all the devices that the jailbreak will support. You can see the list below:
Here is the list of devices that are known to work for sure :
iPhone 4
iPhone 4S
iPad 1
iPad 2 Wifi
iPad 3 Wifi
iPad 3 CDMA
iPod 3G
iPod 4G
Here is the list of devices that won't be supported :