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SHA256 miners that already are merged mining, will know what to do.
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This assumes your litecoind is listening on ports 9334 (RPC) and 9335 (P2P).
If you point your miner to localhost:9327 you will earn LTC, it will be sent directly to your wallet. In addition, without extra cost, you will get free UnitedScryptCoins.
Earn some before the big pools hop on!
Methinks if you want scrypt miners to earn some before pools set this up, you need some better instructions. I like the advice of referring to SHA256 miners will know what to do when the topic is aimed at scrypt miners.....
Windows instructions would be helpful because I don't any about setting up merged mining in Windows even with SHA256 coins. And lastly... why point the miner at 9327 when you have litecoind RPC port as 9334 and P2P port as 9335 in the example? Typo?
I have clarified the instructions.
To answer your specific questions.
p2pool talks to LTC daemon and USC daemon. P2Pool is a local process (python program). Your miner (cgminer/etc) talks to p2pool, and p2pool sends your Proof of Work to LTC and to USC.
Please feel free to ask for more clarification if I am unclear.