DropBox is a nice free (extra storage costs though) program that makes it easy to transfer any kind of file between two computers. You simply set up an account which is linked to your email, then install DropBox onto every computer you wish to link. Dropbox will create a folder on each computer (in a default location or you can choose, I put mine on the desktop for easy access) and as long as the computers are all connected to the internet this folder will sync between them, meaning that files added on any computer will quickly become accessible on every linked computer. Likewise, deleting files in one DropBox folder will cause them to be deleted on every linked computer. So far I've found this to be an excellent way to transfer files from my computer to my Android phone.
Even better, you can share subfolders with other DropBox users. Sara has been sending me media files through DropBox, and I have used it to send a mountain of pictures of Michelle to Mike (her daddy). Once Ann gets hers set up I will use it to finally transfer pictures I've taken at her concerts.
The basic, free subscription gives you 2gb worth of space which is pretty good. The plans for purchasing more are pretty expensive though. If you refer or are referred you get 250mb of bonus space, so use the links I've provided.
This is the best and easiest syncing and sharing program I've found. I've tried using a-drive for this sort of thing but that is more of a backup function and is cumbersome for sharing. I think of DropBox as a