But what I like to do is play the song allong with the original...
Problem is you might forget a part and have to pause, and rewind etc...
So I myself just downloaded the powertab editor, downloaded the song at powertabs.net, turn it on, look at the screen what I have to play, and play allong with it :D
Screw up? No problem, stop the song, go to what ever part you want, press the play button, viola, it starts at the part you want.
I just play allong untill I get it right about 5 times, then stop for the day, the next day I try again, and I can still play it right.
Also, like said above, learn it in peaces, so you can just stick em together :D