Article - http://www.shacknews.com/article/71625/skyrim-online-mod-adds-co-op
(This mod is still in early Alpha Stage, but it still shows the basic chat, and Co-Op play of the mod.)

I know the main concern about a Multiplayer and Co-Op is that it will take away time from developing the main questline, side quests, etc. This mod also allows chat, trade, an arena, and many other new features. But would it really take away a lot of time from that development?

I'm not sure how the modder did this, but it (obviously) allows players to join your game and play together. Without any new Co-Op quests, nothing like that, just you, your friends, and the vast world of Skyrim.

I'm really considering buying a nice PC just to get this mod and various others. I feel left out on consoles.

If you wish to discuss this mod http://www.gamesas.com/index.php?/topic/1316847-skyrim-online-mod/. If you wish to discuss multiplayer in general http://www.gamesas.com/index.php?/topic/1239188-official-tes-multiplayerco-op-thread/.