Im not sure how they do it (abe ?) but I do know you can look up the information using the blockchain.info json api
I have no idea what the satoshidice style payout system is. - (Checked the site http://www.satoshidice.com/, they also mention it "WARNING: Only use wallets that allow you to receive Bitcoin from the same address you sent from.")
I saw this idea on a site (could be bitlotto or raffle site) that said you must send the bitcoin from an address that you can receive from but not using a site like www.instawallet.org to send the bitcoin from. I like the way it is presented on blockchain.info but I do not want to rely on another party to provide me with the info.
I've changed my process to allow the user to manually enter their bitcoin address (allowing for mistakes) and the user will have to wait for 6 confirmations to complete the process.