I'm assuming you are referring to the AMD Phenom II X4 945.
For starters its a sexy quad-core processor clocked at 3.0 GHz.
L2 Cache - 4 x 512KB
L3 Cache - 6MB
Power Draw - 125W
You can order one online for around $140, totally worth the money.
As far as compatible motherboards, any AM3 mobo will work.