Yes. Use you're keyboard.
no
If you are using a wired controller, plug it into the USB. If you are using a wireless, you need to purchase the wireless PC adapter if you don't already own it. Then launch Left 4 Dead, and go to controls and enable the developer console. Then type "exec 360controller" (without the quotes) and press enter. This is will disable the keyboard and mouse, and set up the controls for the 360 controller.
Unless you buy it straight to your desktop, no.
yes but you have to play mutiplayer.
The PS3 controller is necessary to do the vocals, but you can play drums and guitars without having a PS3 controller.
Daisy Fuentes Pilates for Wii can be played with or without the controller. If you do play the game without a controller you will not be able to get feedback on how well you are doing the moves.
Yes, just not any of the dlc
If you take your 2nd controller, and press start, than it will come to a screen where you need to join as a guest or another gamertag.
No the game requires the Playstation Move controller and Playstation Eye Camera, but you can use the Dual Shock 3 controller instead of the move navigational controller
Not if you want to play it
4 players can play in Left 4 Dead 2.
You can't. First you have to buy it and then you have to download the game content from Steam.