I have 4.2.1 and I found this website. It appears to be similar to jailbreakme.com but it wants you to become a member and pay 4.99 before you can jailbreak it. I have a 3GS with ios 4.2.1. Here's a pic for reference. I want to know if it's trusted, and if it works. Thanks for your help.
http://i182.photobucket.com/albums/x260/1998232v6/571c66b4.jpg
http://i182.photobucket.com/albums/x260/1998232v6/571c66b4.jpg