I have seen some mentions of a comic crossover, in which DC Comics Batman meets and possibly fights Marvel's Wolverine. Does anyone know where this is?
After the Marvel vs DC comics Jack B Nimble mentions there is an Amalgam of Batman and Wolverine: The Dark Claw!
I think there are only two issues of that but if I remember correctly they're actually pretty fun stories, with Sabertooth and Joker having merged to become The Hyena. Though I'm afraid that's as close as we get to a Bats and Wolvie crossover.
There is no such match up that is official. In the DC vs Marvel limited series Wolverine goes against Lobo, and Batman goes against Captain America.
Super Power Beat Down did a matchup between Batman and Wolverine
And Pierre Desgranges and Atomic Production did something similar.
I'm pretty sure I've read a Wolverine-Star Trek crossover comic (it was bad) but I don't remember coming across a Batman-Wolverine one. A bit of searching found Dark Claw.
You could also search for fanfic materials. Rule 34¹ will apply, so be careful.
¹ Warning - TV Tropes link! Your productivity will suffer.