It seems that the determined smart phone hacks from the XDA Developers Forum have found a nice way into the file system behind Google's G1 Phone.
Using a small application called PTerminal they have given access similar to the SSH access on the iPhone.
It remains to be seen if this will be as big as the jailbreaking of the iPhone since the G1 is not as locked down.
Read more at ModMyGphone.
Well, it didn't take too long. G1 is jailbroken. Full system access, read and write, has been obtained. And this method is quite easy. A few folks at the xda-developers forum discovered you can start telnet on the device by downloading PTerminal from Android Market, and then you can telnet to the device from your computer.