In order to make up for my lapse, I spent some time playing the online multiplayer demo available in Xbox Live Marketplace. Boy was I confused. I didn't know my enemies from my friends and I couldn't even figure out how to switch my weapons. Well, after a good hour of playing it, I got the hang of it and now I find it fairly addicting.
If you're having trouble getting the hang of it you can check out the 'Lost Planet' help thread over at the Lunabean Nation forums. I made an entry discussing, Lost Planet online multiplayer basics. Enjoy!