Use this website my friend
http://buyersguide.macrumors.com/
ie:
Product iPod nano
Recommendation: Buy Now! - Product just updated *
Notes * Sixth-generation iPod nano available for pre-order as of September 1st, 2010. Begins shipping the following week.
Last Release September 01, 2010
Days Since Update 17 (Avg = 304)
Recent Rumors
09/09: Notes on Sixth-Generation iPod Nano: Teardown, Video Playback Hints, Photo Slideshows, Voice Memos
09/08: Fourth-Generation iPod Touch Does NOT Have Vibration
09/08: Fourth-Generation iPod Touch Offers Only 256 MB of RAM
09/08: iMovie 1.1 for iOS Adds 4th-Generation iPod Touch Compatibility, Video Clip Splitting, and More
09/08: Fourth-Generation iPod Touch Teardown in Progress