http://rpm.pbone.net/
If there is a specific package you're looking for, type it's name in the search field and hit "search". Most packages from here are available via MCC after you set up your repositories from the link in {BBI}Nexus{BBI} post, but not all, there are many 3rd party software developers not affiliated with Mandriva that make rpms for Mandriva, (anybody can), rpm.pbone tries to collect as many as they can.