While I'll list all the other links, I'd really like you to go visit bit-tech for their nice article, which I'll quote here. Expand to read more and check out other resources.
On top of the new instructions, there are also new power management features, higher clock speeds and larger cache sizes. The dual-core Penryn processors will have up to 6MB of L2 cache, while the quad-core Penryn processors will come with up to 12MB of L2 cache – that’s a 50% increase over the Conroe and Kentsfield cores that come with 4MB and 8MB of L2 cache respectively.
Source:Intel 45nm technology overview
AMDTech: Intel Demonstrates new 45nm Transistors and Conroe's Successor
PCPer: Intel Demos 45nm Up an Running