iPhone FAQ has posted the instructions to downgrade your iPhone from software version 1.1.3 to 1.1.2 or earlier which is great news for those that want a jailbroken iPhone, but already upgraded the software.
It was originally thought that there was not going to be a way to downgrade the new iPhone software because of the new underlying firmware that was put in place, but iPhone development community has pulled through once again.
If you are looking to downgrade the iPhone from version 1.1.3 to an earlier version then you should head on over there so that you can once again modify your iPhone.
In case you are wondering about the picture on the right, it is from my movie review blog; Dave's Movie Reviews.
