There are a handful of public
P2Pool nodes open for people to point their miners to. No need to run
P2Pool yourself, and coins generated will generate directly into your wallet. Check with the exchanges first to see if they can take generated transactions for deposit directly, some can, some can't.
I don't believe
P2Pmining.com sends generated coins directly, but sends normal transactions for payouts, so sending direct to an exchange shouldn't be a problem. They also merge-mine. I have not used
P2Pmining.com myself, however, so I may be mistaken on a detail or two for them.
The public
P2Pool Server List is here.
P2Pool operates as
PPLNS, and has a BTC and an LTC network.
-- Smoov