Originally Posted by: JoR0so whats the difference between all of those different A's? is it simply a different timbre from different string gauges or is there a pitch difference too?

Both.

Some of them are the same note on different strings, in which case you have a difference in timbre. OTOH, some are different pitches, the note "A" an octave higher or lower.

Look here for more info:

http://www.guitartricks.com/tutorial.php?input=453
http://www.guitartricks.com/tutorial.php?input=370
http://www.guitartricks.com/tutorial.php?input=419

Hope this helps.