Centrino is Intel Marketing name. The laptop needs to be
1) Intel Pentium-M processor
2) Include Intel WIFI
3) Board using Intel Chipset
With those 3, it qualifies as the "Centrino" brand. Buying another system that uses for example, Intel 855 chipset board + Intel Pentium-M, however no-wifi (buy your own linksys or netgear) will yield the same performance, just no Centrino brand on it.
Cheaper in price too!