After around 1 week of solid processing at 10 gh/s via p2pool network I received 0.00337845 BTC; after missing 16 block payouts in a row.
I'm sorry to say this can't be giving me my fair share for my work done on the p2pool network so I have moved off it.
You may have something wrong with your miner setup, or with the pool you're using - how many p2pool 'shares' did you submit ?
There is some element of 'randomness' - but a week of 15Gh/s has found 17 P2Pool-type 'shares' and apart from the 2 days when that miner had found no p2pool-shares, I've been paid on every block found.