I like using ROM Manager for CM. If it is supported on your phone it will come up in the custom rom downloads list. However if you want a different rom, ROM Manager is not an all inclusive list, it just grabs the most popular, so don't treat this as the only place to go.
CM is popular enough that it will be in the downloads list if it is supported by your phone, so if it's not there yet, just wait until it is. ROM Manager also allows you to back up your current rom (I'm not sure if you need ROOT permissions, but if you're flashing a new rom you will have them), so just back up the factory rom using this app and if you ever need it just boot up into recovery and restore the rom.