What type of cpu socket does the intel iMac have?

hi, i have an intel imac 17"

Hardware Overview:

Model Name: iMac

Model Identifier: iMac5,1

Processor Name: Intel Core 2 Duo

Processor Speed: 2 GHz

Number Of Processors: 1

Total Number Of Cores: 2

L2 Cache: 4 MB

Memory: 2 GB

Bus Speed: 667 MHz

Boot ROM Version: IM51.0090.B03

SMC Version: 1.8f2

i was wondering what type cpu socket it has and is there a limit to how fast the clock speed of new cpu can be? also does the bus speed or cache or anything have to be the same? thanks