Yes, of course they do. These laptops are designed specifically for Linux. These are probably the first main-stream devices where Windows was the afterthought rather than Linux. All of the hardware (WiFi, SD reader, external VGA port, etc.) works with the pre-loaded Linux OS out of the box.
~Bradley
Do these have a working wireless card (not just in there for Windows) in them for Wardriving (securing networks)? Right now I am using a bootable cd distro and a USB hard drive or memory stick for my transportation needs, but there are times a laptop would be nice. That is the one application that I both would like to play with, and get tired of having to use a relatives laptop, when he screws up his network for.