Well, it "sorta" works. Normal Wine, afaik, is not yet able to play Diablo (as of build 20030813). WineX, on the other hand runs it..."sorta".
First of all, any version less than 3, forget about it. I've never gotten the game to come up with anything but 3, and 3.1 made some big improvements.
That said, you'll probably get a menu like this:
(if any of the images fail to load, just do the "copy the link into the browser" trick...was just the closest webspace I had)
http://www.geocities.com/danielv@snet.net/...iabloscreen.png
You'll have to feel your way around the menus, unfortunately :-/ Also, if you choose Battle.net (patch outside of the game!), you'll have to manually select your Gateway by editting a registry file. Fortunately, it isn't too complicated. Just head to your .winex directory (in your home dir), and edit userdef.reg (almost positive that's the name. Just look for the .reg file with "uswest, useast, etc" in the text ;) ) Remove any references to the Gateways you don't want (leaving just one), and you're set.
Just to prove it works :)
http://www.geocities.com/danielv@snet.net/.../diablogame.png
http://www.geocities.com/danielv@snet.net/...t/bigdiablo.png
Just a note, though...it is FAR from stable.
Good luck ;)