I think Centrino refers to the whole package of capability. This is from wikipedia, but just search for centrino.
"To qualify for a Centrino label,
laptop vendors must use all three
Intel qualified parts under each platform. Using only the
processor and
chipset will carry the
Pentium M,
Pentium Dual-Core,
Celeron,
Intel Core or
Intel Core 2 label instead."
Edit: Ho hum - both up too early on a Saturday morning!
