The Folk Music Instruments page covers a lot of terrain in a single page of links.
Check out some history and a sea of lists on this site about the Theremin.
Some sites offer chords and lyrics for specific bands' songs:
Or just let Tab Robot do the searching for you.
Check out these helpful online guitar lessons:
Work up your chops over at the Jazz Improvisation Primer so you can transcend written music and impress your friends.
If you're dying to figure out how a famous player got that certain guitar sound, check out the snappy Guitar Geek site. It's revived nicely after languishing for several years.
If you want to make your own effects (stomp boxes and up), check out the links at my Guitar page.
If soldering isn't your thing, or you are still trying to get a feel for how various standard effects work, I have been very happy with my Digitech GSP-21 Legend and commend it as in inexpensive introduction to guitar effects.
Solid info on all types of guitars can be found online, courtesy of Guitar Notes. If you're like me, you need all the help you can get!
Gruhn Guitars in NashVegas hosts another fine collection of guitar and musical links. Too bad they can't keep 'em all in working order, but I should talk!
If you play country & western music, you probably spend much of your time as a human jukebox. Check your cover repertoire against the Top 100 Country Songs of All Time.
Once you get your musical thang happening, book your own tours: 1 2.