Just a heads-up for anyone running RHEL 5 or a clone (CentOS or SL). The latest update to rsync, version 3.0.6-4.el5, may break any backup scripts you have that rely on the remotehost:remotedir notation to access systems via ssh. Red Hat's package for this includes a patch that breaks this unless you prepend the username@ part before the host name. I had that nasty surprise this morning after yesterday's update.
Your options are to alter your backup scripts to use the user@host:dir notation, or to exclude this update until they release a fixed version. If you've already installed the update, "yum downgrade rsync" seemed to do the trick to revert to the 2.6.8-3.1 version on my SL 5.6 systems.