The 2G isn't something that will be immediately broken. All of the previous iPhone platform products have used the same processor with the same GID encryption key, the S5L8900. The iPod Touch 2G uses a S5L8720 with a different, unknown GID. It is not currently possible to decrypt the 2G firmware, which means it's not even possible to begin trying to jailbreak it. Someone is first going to have to find a security exploit on the 2G (probably at an OS level) so that they can make a 2G decrypt the firmware and spit back out the decrypted product, at which point firmware analysis can begin and vectors for modified firmware jailbreaking (i.e. "pwn") can identified.