There's a new Libertarian blog called Mindarchy. They only have one post at this point. I have no idea if they'll be any good or not.
But look at the blogroll.
Cato @ Liberty
Reason: Hit and Run
The Whited Sepulchure
There's the lowly Whited Sepulchre blog, stuck in the middle of all those libertarian heavy hitters like Reason, Samizdata, Volokh, Sullivan, etc. It looks like one of the easier "Which One Doesn't Fit?" questions on the ACT or the SAT.
Good luck, Mindarchy, whoever you are.