Lion ships with the same version of rsync as panther did. Version 2.6.9 is great and all, but its a bit outdated. The newer versions of rsync allow you to do some better stuff, and along with some patches for OS X (by Mike Bombich) it is a great tool for Xsan volumes as well.
First fire up Terminal.app
tar -xzvf rsync-3.0.9.tar.gz
tar -xzvf rsync-patches-3.0.9.tar.gz
patch -p1 <patches/fileflags.diff
patch -p1 <patches/crtimes.diff
patch -p1 <patches/hfs-compression.diff
sudo make install
Once you have completed those steps you will find rsync version 3.0.9 with those patches applied in the /usr/local/bin/ directory. Make sure when trying to use this version instead of the version included with Mac OS X Lion to specifically call the version in /usr/local/bin/. For example to use this version use the following line:
sudo /usr/local/bin/rsync -aNHAXx --fileflags --protect-decmpfs --force-change /source/ /dest instead of:
sudo rsync -aNHAXx --fileflags --protect-decmpfs --force-change /source/ /dest
It will save you a large headache. If you have any questions about patching rsync 3.0.9 leave a comment or email using the contact button above.