I jail broke my iPhone 3G and it now it freezes and I cant make calls

Do a full backup of your iPhone before doing anything technical to your phone.Jailbreak the iPhone again and maybe it will repair the corruption If you decide to Jailbreak the iPhone again after the restore go for it but this time do not install your application yet and make sure you can dial out. This will help us understand what happened before. If everything seems to be working ok that means an application was conflicting with the Jail broken system.

I have 1.1.3 unlocked, activated and jailbroken now what?

Now download a firmware.

Then hook up to itunes 8.0, it will recognize the phone. Then press shift+restore and select the firmware you downloaded. Then you are done!! Nothing else is required...No coding or programming of any kind. You can use the phone as normal.