I see that there is a subversion plugin for npp, but I didn't see anything similar for github. I want to be able to type the commit messages straight in notepad++ editor rather than git command line.
Is there one?
Git is generally designed to be fairly independent of editor.
If you're working on Windows, have you considered msysgit?
There's also a TortoiseGit, if you're familiar with TortoiseSVN.