I already use SocialScope's builtin FourSquare features.
Unfortunately, they suck for now. If a venue doesn't exist, you're left to input the venue's name. You cant even add the venue or find friends. Meaning I have to go to my MacBook, add the venue so that next time it's hopefully there. Seeing as this didn't work due to the location accuracy of Socialscope at times, I'm less than impressed with the implementation.
Mashable basically did everything FourSquare asked beta testers not to do (screenshots, feature review, etc.) except Mashable did not post the link. Many people on Twitter were RTing the link yesterday night. The link has been changed. I was invited to the beta on one account yesterday and invited later on another account today... different link. And no, not posting it. :P Sign up on the 4sq.com website and you will be invited. Until then, the mobile web interface isn't half bad either.