drag the entire session folder...which will include session file, audio files and fade files.
You will get a Disc allocation error when opening it up the first time, but just click past it.
You'll also want to check what version your friends have of Pro Tools. If they have anything below 7.0 you'll need to save your session as a 6.x file. Also, if they are running PC you'll need to make sure you have the Mac/PC compatibility option checked...you should have done it when you created the session...otherwise you'll have to do a Save Session Copy In.