TF2: Reaping the benefits of the recent upgrades

I've noticed since a major update for Team Fortress 2 you can now (somehow) earn new gear (weapons and stuff) for the classes.

I'm just really curious to know how you go about that...

Is the certain awards to be earned to unlock these goodies or is there some kind of "XP" system?

Each class (well, 3, pyro/medic/heavy) has a set of achievements now, each 12 that you earn unlocks a new weapon (or sandwich)

have fun, go set some people on fire

While it sounds cool at first it ruined the game for me, so much class imbalance.

That and with Dual Monitors it doesnt realize that there are 2 or something? while TF2 is open I can move my mouse to the second monitor yea ... sounds cool .... but then when you move it back the mouse cursor is invisable :(