Where can I play Co-op?

All I see is Deathmatch levels. I've tried everything except Doom Connector.

Zdaemon

I have that, every server on there is DM.

Honestly, there is no reliable co-op servers at your service all time online, neither Zdaemon nor Csdoom. If by any chance that you can find some decent hosts, the community would be appreicated for your support. If you have connection such as DSL or cable or connection above that, you may try to launch your own server for co-oping. You may also want to request from Lyfe, the host of GetSomeWhere, for co-op servers hosting, he might be able to serve you. Lyfe can be met at irc.openprojects.net #Zdaemon

Eh, no luck there, I have AOL :(

Try to get Lyfe, might be the only chance.

Whooo...finally some popped up on IDE, CO-OP rocks.

Yeah, co-op games are the best, but unfortunately decent ones are quite rare on csDoom/ZDaemon.

I just played on a ZDaemon co-op server that was so laggy I saw an archvile performing the Moonwalk :D