PB Blast it a couple of times for a few days. Let it really soak in.
You can always try heat also, just be careful as there are fuel lines right above you.
I've done the big breaker bar and crank method as well. Dont hold the key and try to start it, just click it over until you hear it try to turn, then back off the key. I watched an idiot start his car with a breaker bar on the pulley...the socket did not want to come off and it beat the living crap out of a bunch of things. All you want to do is break it loose and remove it by hand after that.