I had a jailbroken iPhone about a month ago... got a new one, still a 3G, from Apple, assuming a refurb. I just jailbroke it today.
It worked a few times but would quit. Restarting the iPhone seems to make it work, but it quits after 3-4 text messages.
I also have LockInfo if that has any involvement. My iPhone is 3.1.2 jailbroken with pwnage and on AT&T.