How do you unbrick an iPhone 3GS 3.1.3 with a brand new prepaid sim card?

[stradi]

Edit

[i.Annie]

If I were you I'd sell the thing and buy a new iPod Touch. I mean, you're not going to use it as a phone anyway. Some AT&T user out there would buy it for well more than what an iPod Touch costs, might as well grab the cash and a new iPod. 3.1.3 is jailbreakable at this time. I'd just make sure to get an Ipod that is fully jailbreakable (non-tethered I mean)