Kimbo is sitting as a pretty heavy favorite here.
Bodoglife.com has the fight currently at:
Kimbo Slice -350
Tank Abbott +275
Odds that wide on a fight like this makes me want to throw a little bit of money on Tank. I think Kimbo will win, but when the two start throwing shots either guy could land. And both guys have heavy enough hands that it could end the other guy's night.
Slice will likely be able to use his underrated head movement to get into position to throw the shot that will be the beginning of the end for Tank. But again, if Abbott can manage to land a right hand he could pull it off.
Again, Kimbo will likely win...but this is the style of fight where those odds get a little bit tempting.