From VDR Wiki
Mini-ITX is a formfactor for motherboards like AT or ATX. The boards are supposed to be used in embedded applications where soem desktop alike equiment is needed. Popular are motherboards from VIA with C3 or EDEN processor using the EPIA chipset (I hope I am not totaly wrong about the chipset). These are x86 derivates with low power consumption and clocked up to 1.3 GHz.