Orgcoin is running a merge mined LTC/ORG pool.  It would be trivial to add USC to it.  At the moment my p2pool debug logs seem to indicate that p2pool thinks Orgcoin IS USC (we share a common codebase so it's not surprising).  Once I get that resolved I'll add USC to pool.orgcoin.org and you'll be able to earn USC & ORG while mining for LTC.