Great! I had trouble with vmprof at 2.6.0, so I'm looking forward to giving it a try on 2.6.1.
Ok, the problem is that it seems to not work well in a virtualenv, from what I've seen (both 2.6.0 and 2.6.1). Outside of virtualenv, the _vmprof extension gets built automagically, but that step got omitted in the virtualenv install (via pip).