KGuitar!

MuseScore is a free music notation and composition software available for Linux, Windows and Mac.

With TuxGuitar, you will be able to compose music using the following features

Guitar Pro is first and foremost a program designed to edit tablatures for guitar, bass, and other fretted instruments from 4 to 8 strings.

Songsterr is an archive of guitar, bass and drum tabs. It is collaboratively built and maintained by your fellow music lovers. Anyone with Internet access can contribute new tabs and make changes to existing ones. Much like Wikipedia, contributions cannot damage Songsterr because the software allows easy reversal of mistakes and experienced editors are watching to help and ensure that edits are cumulative improvements. Begin by simply clicking the edit link near song name on tab page.

Impro-Visor (short for “Improvisation Advisor”) is a music notation program designed to help jazz musicians compose and hear solos similar to ones that might be improvised. The objective is to improve understanding of solo construction and tune chord changes. There are other, secondary, things it can do, such as improvise on its own. It has also been used for transcription. Because rhythm-section (e.g. piano, bass, drums) accompaniment is automatically generated from chords, Impro-Visor can be used as a play-along device. Now having a wider array of accompaniment styles, its use is not limited to jazz. »

Guitarix is a simple Linux Rock Guitar Amplifier for JACK Audio Connection Kit with one input and two outputs. Designed to get nice thrash/metal/rock/blues guitar sounds. There are controls for bass, middle, treble, gain (in/out), compressor, preamp, tube's, drive, overdrive, oversample, anti-aliase, fuzz, balance, distortion, freeverb, impulse response, vibrato, chorus, delay, crybaby(wah), ampselector, tonestack, and echo. For 'pressure' in the sound you can use the feedback and feedforward sliders. »

Noteflight is an amazing online notation editor. On the free version you get 10+ instruments to choose from, lots of musical symbols and more. On the payed version (Cresendo) you get lots more instruments, guitar tab and sharing options. Best way to wite music on the web.

Canorus is a free cross-platform music score editor. It supports an unlimited number and length of staffs, polyphony, a MIDI playback of notes, chord markings, lyrics, import/export filters to formats like MIDI, MusicXML, ABC Music, MusiXTeX and LilyPond.

Power Tab Editor is a free tablature authoring tool created by Brad Larsen for Windows. It is used to create guitar, bass and ukulele tablature scores, among many others. The current version uses the *.ptb file format.The Power Tab Editor is able to import MIDI tracks, and can export to ASCII Text, HTML, and MIDI formats. In addition, individual sections may be exported as bitmap files.The program allows for tablature scores to be created alongside standard musical notation. The software achieves this through the input of tablature.Each Power Tab file contains two scores: guitar and bass. Only one score needs to be used for a Power Tab file. For proper playback, it is required that the time signatures and tempo markers be consistent between the two scores.The latest version was released in 2000. In 2006, the author released an open-source wxWidgets based program named the PT Parser. This code contains useful information for developers who want to write software that can convert, view, play, or edit Power Tab (.ptb) files. The PT Parser project is hosted at Google Code. »

DGuitar is a Guitar Pro (*.GP4,*.GP3,GTP) viewer/player that works on Windows, Mac, Linux, BSD, Solaris, and any other operating system that has Java Runtime Environment 1.4 or later installed.

TabIt is a full-featured program for creating, playing, and printing guitar, bass, or banjo tablature.

Band-in-a-Box is so easy to use! Just type in the chords for any song using standard chord symbols (like C, Fm7, or C13b9), choose the style you'd like, and Band-in-a-Box does the rest... Band-in-a-Box automatically generates a complete professional-quality arrangement of piano, bass, drums, guitar, and strings or horns.

TabToolkit for iPad, iPhone and iPod touch is an incredibly powerful music notation viewer with multi-track audio playback. The app includes an audio synthesis engine that enables you to listen to and control the audio for all instrument tracks individually. TabToolkit makes learning how to play your favorite songs on guitar, bass, keyboard, drums and other instruments easier and more fun.

Reflow is a music notation app that runs on iPhone, iPad and Mac. It is a 100% Native app that supports iCloud sync and latest Mac OS X features such as Versions, Autosave and Fullscreen.

Guitar Partner (former TabDroid) is a tablature player for Android friendly mobile systems (Google phones). Two versions of Guitar Partner are available: Guitar Partner Lite and Guitar Partner Pro which has extra features.