Where did my coins get sent to?
Your coins got sent to the address the client says they got sent to.
There were two transactions created at the same time.
About the only time I've seen that happen is when someone is purposely attempting a double spend themselves.
Did you use the Bitcoin-Qt client to send the one?
At this point, you might want to treat your system as "status: potentially compromised" and power down your system. If your wallet still has funds, you might want to copy the wallet.dat and from another system send those funds to safety.