CyanogenMod replaces ROM Manager with CM Updater

ROM Manager has always been the way that Android root users could easily flash a custom recovery, or check for and download updates for custom ROMs. A few custom ROMs have been supported, so the app may continue in some form, but if you're a CyanogenMod user and don't have an interest in any other custom ROMs, there is now a better way.

This seems like something we should have seen a while ago, but CyanogenMod may be working towards retiring the ROM Manager app for updates going forward. The change can be seen to start in the newest nightly builds of CyanogenMod 10, which now include CM Updater. CM Updater can be found in the settings menu and will allow OTA updates of your device. 

The CM Updater settings don't yet support all of the features of ROM Manager, like flashing custom recovery or downloading add-on installs, so ROM Manager will survive for a little while at least. But, at least the process of updating your device will be a bit easier for CM users.