Firewire, also known as IEEE-1394 and iLink, is a high-speed serial bus system that was originally developed by Apple Computer. Currently, its widest implementation is for digital video; however, it has a lot of other uses. Like USB, Firewire is a serial protocol that supports hot-swapping. Firewire supports much higher speeds than USB. The Linux IEEE 1394 Subsystem provides support for IEEE 1394 (FireWire, i.Link). It consists of a kernel subsystem as well as applications.
Also I have set up a page collecting information about laptops and FireWire at TuxMobil - Mobile Hardware Survey .