ROM manager just utilizes CWM. It enables you to select a zip file and load it through the app..then that will reboot and do everything for you in CWM.
Just an easier way to backup/recover.
I second the notion of getting some of these ROMS up in Rom Manager. Just contact Koush directly via twitter or #koush on freenode, im sure he will be more than happy to give anyone interested the proper information to get their releases in Rom Manager.