...still play any of the following games in multiplayer on Xbox LIVE?
Tom Clancy's Rainbow Six: Lockdown
Brothers in Arms: Road to Hill 30
Brothers in Arms: Earned in Blood
Star Wars: Battlefront II
Call of Duty 2: Big Red One
Call of Duty 3
Thank you for any help!

I'm sure they do, but it could still be hard to find matches. I don't see many people playing CoD 3, because CoD 2&4 were alot better than that game. I know Star Wars: Battlefront II still has people playing it on the PC. It may take some time to find matches, but those games aren't really that old, so you should find be able to find a game.

Original XBox Live? You'll mostly find Halo 2 and nothing else.

Sad... but mostly true.

You'd be surprised.
http://majornelson.com/archive/2009/03/31/live-activity-for-week-of-march-23rd.aspx

Are you sure you're not thinking of Battlefield 1942?

Nope, it is.

Wow. That's cool. Never heard that. The first Call of Duty was sweet.
Hmm, maybe a gog someday? :D

Yep, they're going to put up the first Call of Duty as a downloadable on PS3 and XBox 360.

Surely it'd be xbox originals rather than an XBLA game. Rumour is they're doing that for Max Payne 1 & 2