Is jailbreaking your iphone 4 any good?
Yes, jail breaking an iPhone 4 will be a good idea. You will get a chance to add more applications in your phone and unlock it from iTunes. You can go http://www.ehow.com/how_10040088_jailbreak-apple-iphone4.html to and get the steps on how to go about it.
If u are interested in fiddling, then jail break it. Try this link. http://www.iphone4jailbreak.org/download-redsn0w-0-9-10b2-redsnow.html