I posted this in anoter topic, but I posted it in a dead topic so I thought that I would put it here since a lot of people seem to want to play this multiplayer.
There is a launcher available at suprnova that is supposed to allow multiplayer. Since the other methods talked about do not seem to be working thought y'all may be intrested.
Quoted from readme file, with some modifications to make it clearer what is being said.
This files is available at suprnova, I do not know if it works, do not like online, but thought I would share it with those that do.Place in the same folder as your Halo executable, otherwise you'll get launch errors.
Thanks to Peopls for finding the -connect shortcut line!
*****To Create a Game***** person to be connected to go into halo game and do the following
multiplayer>create or edit gametype (or whatever)
>select a gametype to edit, the one we just played was CTF pro
>change the name to something else
>set all the settings to how you wish
-for vehicles, for some reason you can't have both auto cannon and rocket warthogs in the same game, a bug maybe, also makesure you specify the vehicles for both teams)
>go back to the mp menu,
>under create game, click LAN
-you will see a list of maps, the one we just played is at the top i think, if you select another map, and you get a message saying that a file can't be found, this means that the map is unavailable.
>select a map
>for the gametype, change the listings to custom at the top, which should wipe the list and show the gametypes you have created
>select your gametype
>set up max players and start the game,
ignore the IP there (but leave it as it is) its for a LAN game, use your ISP Client IP
Give your ISP client IP to the people you want to connect, tell them to put it in this app,(the application for download on suprnova) voila!
Sorry it others did alreaddy read my post in the other topic, but since this is a pretty hot topic thought I would put it in the open for y'all. Let me know if it did work, and if anyone wants to test it PM me and will do that much. I am bored.
EDIT: damn i just spammed, I hate spam I read back a couple of pages on the leaked halo thread and this is kind of in there. SORRY.