So I've been learning to play the guitar for around 3 months now.
It's coming along well :)
I figured I'd plug Tuxguitar and a few sites/apps I've been using.
Windows users might know of Guitar Pro which is a software that allows creation of tabs and plays them back.
However what most users dont know is that a free (gratis) and open source equivalent called tuxguitar exists.
This will be very helpful when viewing the *.gp3, *.gp4 and other files that are available on various guitar tab sites.
(Or view those rumoured hundreds of thousands of tabs I'd heard are available on some peer2peer technologies ;) )
It is written in Java and is thus available on Windows, Linux, Solaris or any architecture with a JVM. Tuxguitar in the Ubuntu 8.04 repository has known sound issues on AMD64.. so you better get the latest version directly from the site.
Also very useful to practice your strumming is GTick (On ubuntu simple apt-get install gtick). One good page to learn strumming is here.
Happy guitaring.