Feeware CPU-Z is a program that provides some information on your CPU :

Processor name and vendor
Core stepping and process
Processor package
Processor current core voltage
Internal and external clocks, clock multiplier
Partial overclock detection
Processor features, including supported instructions sets.
L1 and L2 cache informations : location, size, speed, technology.
Motherboard informations : BIOS, chipset, memory, AGP. What's New

New cpus support : Athlon Thoroughbred (0.13µ), Celeron P4, Pentium 4-M.
Pentium 4 socket designation revisited.
Mobile AMD processor detection enhanced.
BIOS release date.
Refresh button.

Download CPU-Z v1.13 for Windows 95, 98, Me, NT4, 2000 and XP