While the multiplayer reveal for Call of Duty: Modern Warfare 2 will take place at a different date, we did learn a few nuggets of information today alongside the worldiwde campaign reveal.
According to various previews, the game will feature a revamped Gunsmith with more customization than prior, allowing you to progress multiple base weapons that are part of the same family.
New gadgets will be available, including a field cam which you can remotely operate to see if there are enemies nearby. Another piece of equipment is a DDoS device (thanks, IGN) which releases an EMP charge to stall enemy equipment and vehicles. There's also a Drill Charge that you toss on a wall or vehicle. After it drills a hole into the target, you can toss a grenade into the opening.