Most pools don't distribute funds to their users until 120 confirmations have been reached so none of the coin that they mined will show up in their users' accounts. The only way this could cause problems is if the pool's maintainer is somehow still mining on the 0.8 branch which would not happen as the 0.7 branch blockchain has surpassed it in length.
If you are solo-mining and you found a block on the 0.8 branch of the fork, the standard client prevents spending newly minted coin with less than 120 confirmations. It will be the same as what happens when you get any other orphaned block, the funds will just disappear.
If you are solo-mining and you found a block on the 0.8 branch of the fork, the standard client prevents spending newly minted coin with less than 120 confirmations. It will be the same as what happens when you get any other orphaned block, the funds will just disappear.