the legality of using the msn chat ocx seems to be a very hot topic that has no clear cut answer. To be honest I wouldn't bother with it. I would focus on finding a nice host that supports ircd hosting.. https://the-irc.com/ is a good site ( we have used their services before ). I think the chat ocx is quickly becoming a thing of the past. The future seems to be in ajax ( or at least that seems to be the current trend ).
Please don't take this the wrong way but there are hundreds and hundreds of chat servers out there. Some very well established ones. To be honest unless I had the knowhow to edit and control my own server as well as create and control my own chat system ( be it ocx, ajax, flash, or whatever ), I would not worry with running my own network. I speak from experience when I tell you running a chat server is a lot of work.
My suggestion would be to start looking into how to run/edit something like unreal and go from there. In order to run a successful chat service you will need to understand all the options at your disposal. It's not a small undertaking and many chats never make it very far because their creators do not have a good understanding of what they are doing.
But if your goal is to do one yourself by all means go for it. I am not saying you shouldn't. What i'm trying to say is it takes a lot of work and the know how to get a good chat going and making sure it stays around.
https://the-irc.com/ is a good place to start. Like i said we have dealt with their company in the past and the owner helped us personally with everything we asked of him.