How can I change Halo Custom Edition to play online on v1.00? I've heard there is a lot more servers and players. I currently have v1.09. My guess is that I enter a command line argument, but I have no clue. Some help would be appreciated.

you need halo version changer:http://goemitar.wordpress.com/2008/08/21/halo-version-changer/

to switch to version 1.00 you type: "version 1.00ce" in the console

thanks! funny you mention it, i just saw that on a google search trying to find the answer, but is it safe? looked kinda suspicious

More or less. Thing is is that when you change the version, you have access only to playlists and servers using that version. To restore access to any one version requires you to change the version each time. I use it to enable flycams and 3rd person hacks during campaign, though haven't been using it because STL (Sky's The Limit) works with 1.09.

Version changer is really just two executable files: your Halo: PC and Halo: CE exe's. Replacing the default ones in your directories with those of version changer gives you access to changing versions via command line, but if you fail to back up the originals before overwriting, and you encounter a problem with/caused by version changer, then you have to reinstall that game.

Ok so i got it and it works fine, but i dont recall changing any exe's, just replaced the strings.dll and added versionchanger.dll

You're right, it's not EXEs. Those DLLs are just application extensions for Halo that you need to be able to do the version stuff.
EDIT: Spelled version as venison
Edited by SlappyThePirate on Sep 5, 2010 at 01:26 PM

Uh-oh. Then what the heck did I download? It came with the dlls and some new exe's...nothing out of the ordinary has occurred as a result. Odd.