I went out with a friend last week, and he invited 2 girls that he works with to come out with us. These two girls work in another state selling products to different accounts. He refers to them as coworkers. Which I totally disagree. They work in a different state selling to different accounts. I want to take one of them down. He doesn't want me to, and he's not helping with the situation. I want to FB her, but he doesnt want to give me her last name. I feel he's being a douchebag/cockblocker. I know there are other girls to go after, but I feel he's ruining this chance that I have.

This shouldn't be a matter of who is right or wrong. Right now if we tell you you're right that doesn't accomplish anything.
There are a couple things to consider
1) Is your friend interested in the coworker? (and judge by his body language when you ask about her (see if he gets defensive) or if his body language changes when you bring up the matter of you trying to sleep with her that he gets defensive)
2) Is his reputation on the line in any way (are these coworkers possibly going to be coming to the state again/moving to the state/getting a promo any time soon)
3) Buddy just drop it. He was good enough to take you out with him to meet these ladies and if you make a big deal about it this time he probably won't bring you along next time. If you suck up your pride and say 'alright sorry man' he'll at least see that you were man enough to apologize. Don't forget, you had the opportunity to snag her number or last name for fb when you went out for drinks the first time and didn't close. It's not your buddies job to pass that along (even though it is a bit of a douche move and I wouldn't have hesitated to give it to you.)