I've played guitar since I was about 15. These days I play an acoustic steel-string guitar—a Taylor 310-CE if you're interested in that sort of thing. Mostly, I figure out songs that I like and then sing as I play. If I really like a song then I'll spend the extra time memorizing the lyrics. But that takes a lot of time so I don't do that much anymore.
Before I had the iPad my routine would be to Google the song name and add the word 'lyrics' or 'chords' (the latter if I was too lazy to figure the song out myself). After I found the chords/lyrics, I'd print them out and put them on my music stand and plunk away. My music stand has a slew of paper on it, and it's hard to find songs now using the paper.
Then I discovered how to do the same thing, in a much easier way, with my iPad.
The folks at UltimateGuitar.com have an iPhone app called Ultimate Guitar Tabs (sadly not optimized for the iPad yet) that costs like $2.99. It lets you search for songs based on artist or name, thus quickly giving you access to the lyrics or chords. On the iPhone the display was much too small to read. But on the iPad it's perfect.
And you can bookmark songs that you like so you can come back to them later. This is much better than shuffling through reams of paper (my long-standing tradition). But wait, there's more! The app has an 'auto-scroll' feature that slides the lyrics up slowly so that you don't have to reach over to scroll up when you get to the middle of the song and need to see the rest of the lyrics. You can even adjust the rate at which the music scrolls.
There are other apps for reading music such as TabToolkit (iPad optimized; $9.99) and I'm sure a whole slew more are on the way. I wish that I'd had stuff like this when I was learning to play guitar, but it probably did me good to learn how to figure things out on my own. Now I'm older and lazier. I just want life to be simpler. And with my iPad it is.