Guitar Pro 5.2

Guitar Pro 5 is one of several highly regarded software packages for music composition and transcription. You should know about it because it's packed with features aimed directly at the developing guitar player.
The Guitar Pro 5 documentation describes the program as "the ultimate workbench" for the guitarist, "aimed at helping the user progress, compose, or simply accompany himself on guitar..."

I describe it as musical notation software built with a guitarist mind.

If you're comfortable with TAB, use it as a TAB editor. If you know how to enter musical score, use it as a score editor.

You can easily switch between TAB and score, or display both at once, so you can learn score from TAB, or TAB from score. If you don't know either, you can enter notes into Guitar Pro using a virtual fretboard or a virtual keyboard.

But entering musical notation or TAB doesn't even scratch the surface of all that Guitar Pro 5 can do for you. You can:

Learn scales
Lookup or build custom chord forms
Playback the music you've entered
Enter lyrics and align them with the melody
Control the speed or playback, or loop sections for additional practice
Print out nicely formatted music
Export to a variety of formats, including WAV sound files.
You can even tune your guitar if you want to! Add all this together and Guitar Pro puts a complete music toolbox at your fingertips that can both assist and consume you!