We have the hosted versions of both and I've heard more than once "I can't believe they(fogcreek) doesn't do something in project management because most of the current solutions suck."

Minimally for now - a FogBugz link in a comment will show a little kiwi icon on the front of the card, which you can click to follow that link. The planned API will likely lead to a plugin.

Man - I would kill for this. We use fogbugz / kiln right now, and integration into these boards for cases / users / pushes would be the icing on the visibility cake.

Joel mentioned plugins so I can only imagine integration will exist at some point.