Ok! I have trawled through the internet and I seem to be even more confused!
I have an iPhone with 1.1.2!
I have tried using the AppTappInstaller but it just resets the phone and is stuck on the iTunes and plug screen - the windows exec program just sticks!
Can I actually use the 3rd party apps on my phone at all!?
yes you can, but this is the wrong thread..
there are plenty of guides on this site to help you, in the top right corner there is a search box, I would start there, or in the Wiki section (click on the W at the top of this site)