If not how does the pool prevent this?
The block that you are solving includes the payout address (so the 25BTC reward is paid to the pool). This cannot be changed without the hash changing too, so if you find a hash it is only valid for that block and hence the pool it was originated from. Sorry, no free lunch for you
![Tongue](https://bitcointalk.org/Smileys/default/tongue.gif)
That's what I wasn't sure about. Thanks.
These two links should keep me busy for a while:
https://en.bitcoin.it/wiki/Blocks
https://en.bitcoin.it/wiki/Block_hashing_algorithm