CMD Command to add preferred wireless networks

Okay, so I'm trying to make my life a little easier for the future as I continue to receive and setup new laptops for my company.  I'm a big fan of batch files which do 98% of the work for me.  Thus I already have a batch that copies all the necessary install files onto the computer, installs them silently, uninstalls all the BS Dell software that comes standard silently, etc.  My next item I'd like to add to that new pc batch is some way to add preferred wireless networks, including the WEP key so that I don't have to manually go in and add them.  I like to do this so that when the laptop is handed out, I don't get a phone call saying 'how do i connect to the wireless?'.  Instead I like it when i've pre-added these wireless networks and the wireless connects automatically when in range.  So to sum it all up...I'm looking for the command that I would need to use to add preferred wireless networks.  Thanks in advance.