I have enabled the epel and remi repositories, but:
yum install rsnapshot
No package rsnapshot available.
rsnapshot was in EPEL on prior versions... was it removed?
Rsnapshot is in the Fedora Repositories, however it looks like it hasn't been built for RHEL6, and the last RHEL5 build appears to be from 2009.
If anything it looks like the package is in need of some love and attention again. This looks like a good chance for someone to get more involved in the open source community!