The other night I was experimenting between the two Palm pdas I own - a Tungsten E and an M130 (an oldie but a goodie) and happened to open the Network Preferences in the Prefs application. I ignored the "service" and "user name" slots, and left "password" at -Prompt-. For "Connection," I selected "IR to a PC/Handheld." I did this on both devices, pointed them toward each other, and tapped "connect" simultaneously on both devices.
Bang. Just like that, they networked! Each had fooled the other into thinking it was online! On impulse, I went to WI and hit multiplayer. Now, for a Tungsten E or an M130 (which is pre-OS5) that option is unavailable under normal circumstances. It still was for the M130, since Multiplayer is only for OS5 and above. The Tungsten E, however, went right to the multiplayer game setup screen! Amazing! Now, if I only had an IP Adress...
I tapped around a little more, going back to the Network Prefs. There, I saw a "Details" button, and tapped it. At the bottom of that screen, there was an "IP Address" option, with "Automatic" checked. I checked off Automatic, and was given the chance to enter an IP address! I entered the one from my computer, and reconnected the two handhelds. Going back to WI, I found that I could, indeed, host a game with that IP address!!!
Now, does this mean you can play multiplayer via infared? Darned if I know. Unfortunately, my little M130 is incapable of multiplayer under any circumstances, and I don't know anyone else who even owns a handheld!
All I was trying to do was find a way to test single play triggers in multiplayer maps (ie - a computer player in a 1-2 person multiplayer level). If anyone out there wants to try actually starting a multiplayer game between two handhelds using this method, go for it!
Personally, I have serious reservations about infared even working, much less working well enough to be enjoyable. (yeah, I think I've expressed as much, before) That being said, it might be fun to try it, just to see how far you can push the limits.
If anyone does try this, throw us a post, here! I'm curious.