The WMP playlist is a simple text file created by WMP. There are files in it. Those are wherever they are on the drive and can be moved from one folder to another and easily copied from drive to drive. But you will need something like a usd adapter for the laptop drive or firewire data transfer cable for direct copy.
The playlist on another machine would be seen under "additional playlists" since there the main ones are created by that copy of WMP installed there. The playlists are usually found in the DocumentsandSettings folder\user name\user name documents\MyMusic\Play lists folder.