cant find airplay on my 2nd gen ipod touch can you help ?

What are you trying to AirPlay to? The AirPlay icon only appears if you have an AirPlay receiver ready to accept the media from the iPod.

Also, see the following. The 2G not hot have iOS 4.3 or higher.

From the Videos, iPod, Photos, Music, and YouTube apps on iOS devices, stream videos, music, and photos to an Apple TV (2nd and 3rd generation), or stream music to an AirPort Express or compatible third-party device.

With iOS 4.3 and later, you can also stream video and audio from a website or a third-party app installed on your iOS device if the developer for the app or website has added AirPlay functionality.