I don't know of one, but there should be. ;-)
This one's pretty nice:
http://www.wrcoffee.com/
This might help too:
http://www.pegasusnews.com/places/coffee-shops/
(That's the day job-- sorry no location search yet...)
I just found this page, which is fallow, but has some leads.
http://coworking.pbwiki.com/DallasCoworking
Note that last edit is about 8 months ago, so the "November" referred
to by Jonas has passed.
However, I think Alex Muse is still in Infomart:
http://coworking.pbwiki.com/InfoMartProposal