CDG Editor is a tool that allows the user to edit the contents of a CDG file (typically extracted from a karaoke disc as mp3+g). v1.3 now supports all CD+G command types.
Please note that this is not a Karaoke creation or editing tools (see some of the comments below) - it is for fixing the CDG files that you have where the text is corrupt due to a poor rip from the original CD+G disk. You have to edit individual CD+G tile commands. This tool could be used to change the lyrics of a song for example, but it would be very difficult - that's not its purpose.
Thanks for the feedback though. I've installed it on several Windows 7 64bit PCs but haven't tested the installer or the app on Windows 8 yet. Let me know via the support pages if you have problems and I'll see what I can do to help.
The MSI file installed fine on my Windows 7 64bit system. However, all it lets me do is edit pixels on the screen - one chunk at a time. You can't go in and edit lyrics by just changing a text entry as I'd hoped.