Possibly is. Assuming they're not:
Hold down shift while booting to disable kernel extensions. This will disable it in that session, but if you reboot it's back.
To remove it permanently, hold apple-s while booting to go into single user mode. Then use the instructions it prints out to mount the filesystem, and use the basic unix commands to delete the kernel extension the keylogger adds. Somewhere in /Library/System/Extensions/.
I rule.