WinCompose - WinCompose supports the standard Compose file format.
Free Virtual Keyboard - Free Virtual Keyboard is a free, lightweight, multilingual and finger friendly virtual keyboard.
PopChar - The character map that works!
Onboard on-screen keyboard - An onscreen keyboard useful for tablet PC users and for mobility impaired users.
BabelMap - Unicode Character Map for Windows
Comfort Keys Pro - Virtual keyboard, automation, shortcuts, flexibility, advanced clipboard management.