A lot of computer software tools and utilities for music production are available; some even for free. These are invaluable resources for musicians and music arrangers.
At the listed web sites you can find a variety of Music Software Programs designed for general or special music production.
Yamaha Keyboard Resource Site - Music Software 2 Music Software 2 
Yamaha Keyboard Resource Site - Drum/Beat and Chord Software Drum/Beat and Chord Software
Yamaha Keyboard Resource Site - Yamaha Keyboard Related Software Yamaha Keyboard related Software

Software Search
What's New at SMM
Audio, MIDI & MP3 SW
Windows Music Software
Shareware - Synth Zone
MIDI Software
Music Software Collection
Sound & MIDI Software For Linux
Yamaha Keyboard Resource Site - Japanese Site Winart music

Lyrics Software
Lyrics On Display
Digital Fake Book

Composing Software
Draw Music Software
Improvisor
Synfire Ultimate Composer Program
jMusicCreator

  Sequencer Software
Wikipedia List of MIDI editors and sequencers
Music Notation Software
Musicator
Anvil Studio
Logic Pro Audio
Sweet Sixteen
Cubase - Steinberg
Cakewalk
Harmony Assistant
Power Sequencer Plus 3
Logic Fun - Free Home Studio
Pizzicato Professional
Propellerhead Software
GVOX Encore
Guitar Pro - Tablature Editor Software
Power Tracks
MIDI Connections
  WinJammer MIDI Sequencer
Turbo Play
Sekaiju
MidiWorks - MIDI File Editor
Brels MIDI Editor
Sekaiju
Multitrack Studio
Jazz++ MIDI and Audio Sequencer
Frinika

Scanning Software
SharpEye Music Reader
Musitek SmartScore
Audiveris Music Scanner

Learning and Practicing Software
Home Concert Xtreme
Classroom Maestro
Yamaha keyboard resource PianoBooster

  Notation and Printing Software
Wikipedia List of scorewriters
Finale Music
Sibelius
Midi Notate - Notation
LilyPond Note Printing Software
MidiIllustrator music notation software
Mozart Music Notation Software
NoteWorthy Software
Chord Pro Songsheet Generator
MuseScore - Composition & Notation
The ABC Plus Project
Noteflight - Online Music Notation
Create Sheet Music
Musette Free Music/Song Editor
MIDI Sheet Music
Chord Sheet Editor Add-In for Word
musink - Beautiful sheet music
MIDI score creator