Unfortunately, while the HST is resolving more as the little planetoid moves closer to the sun in its wild orbit, at the current time it isn't able to resolve fine enough for any detailed surfacing:
A scientist with the HST team responded to an email I had sent him some time ago, explaining why Hubble could give us shots of stars and galaxies billions of light years away, but couldn't share a decent picture of Pluto. I wish I had kept it so I could post the thing here, but it didn't survive one of my occasional 'clean outs' of my Inbox... damn me.
Anyway, I just hope that I'll live long enough to see the images from the New Horizons probe currently speeding its way toward the double planet system (with Charon). That vehicle will arrive sometime in 2015.