Q: Where can I find Power NAP for my Mac?

Only laptops with built-in flash storage have the Powernap feature. That means Airs, and the newer Macbook Pros.

http://support.apple.com/kb/HT5394?viewlocale=en_US&locale=en_US

Matt

both laptops have flash ram

This is not Ram referred to, but an SSD instead of a hard disk.

Unless I'm mistaken, in addtion to an SSD, it also requires an Sandy Bridge Processor (or later) that supports Intel's Smart Connect feature to accomplish it's sleep/wake management for low-power background connectivity, hence why earlier Air's & Pro's may not be able to use it.

Actually, those two models require a firmware update in addition to 10.8 to enable Power Nap. The firmware update will appear in Software Update if your machine is capable of Power Nap.

I got a MBP late 2011, i change the main HD for a SSD 250GB, can i get power nap?

Processor  2.2 GHz Intel Core i7

Memory  8 GB 1333 MHz DDR3

Software  OS X 10.8 (12A269)