I was just wondering where can I find or get the 'online key' for playing online???

thanks

OMG.

This quesion is probably the #1 answered question here.

CD key = online key.

For store copies CD key is on back of booklet.

Digital copies vary, but Steam does a good job of notifying you of your key and usuallyasks if you wanna copy it to your clipboard for easy entry later.