for creating charts, I use printmusic. I love it. you have to pay for the full version, but it's not ridiculously expensive (like Sibelius). it's a really simple program that doesn't take long to learn, too.
as far as learning tunes, I start by figuring out the progression (if there is one), and go from there. if it's a complicated melody or line, I definitely take the time to write it out, because transcribing things for me is just as good as playing it a hundred times (as far as memory goes).
edit: so I just looked at the prices for Print Music, and it's more expensive than I remembered ( about $130). but their other program Finale Notepad is only $10 and works really well, too.
(Message edited by darkstar01 on July 25, 2011)