What are the risks of jailbreaking an iPhone 3G.

Warranty will void. You might brick it. (There are tools to unbrick but dont always work.) You sometimes just mess up the Operating System. Don’t do it. Its better not to with the new App Store and all that.

I didn’t think it was possible.

it voids your warrenty, but you can just restore it before you send it to apple if you ever break the screen or something. as long as your not an idiot, you probly won’t brick it. Just read around and try to find out as much as you can and be careful and make sure you know what your doing.

Just do it.