Team fortress 2 is now free to play and download, but only on the steam marketplace
The Classes

The Scout has the ability to run faster than any other class in the game. This feature helps when you are playing objective type games. Also as a Scout you can double-jump. This helps when you need to dodge bullets.He has 125 health.The Scout has a full auto skater gun, A semi auto pistol , and a baseball bat.

The solider dose not really have a ability, but he dose have 200 health( that is more than most classes) The Solider has a full auto rocket launcher, a shotgun, and a shovel.
When the Pyro get shot with a flamethrower it does not set him on fire.He has 175 health. The Pyro has a full auto flamethrower, a shotgun,and a ax.

The Demoman does not have a ability. The has 175 health. The Demoman has a full auto Grenade launcher, a semi auto stick Grenade launcher, and a bottle.

The heavy Has the most health out of all of the classes.his health is 300 . He has a full auto Mini Gun ,a shot gun ,and his fist

The Engineer has the ability to make sentry guns , despencers, and telaporters. He has a shotgun, a semi auto pistol and a wrench. He has 125 Health

The medic can heal people and can regenerate health. He has a syringe gun, a medi gun and a bonesaw. He has 150 Health.

The sniper does not have a special abillity. He has a sniper that when scoped long enough it makes the bullet more powerful, , a sub -machine gun, and a kukri. He has 125 Health

The spy can turn invisible, disguised as an enemy and back stab people. He has a pistol, a elcto sapper(to destroy turrets)and a knife. He has 125 health
The Weapons
http://youtu.be/cfMn_VnuQm8