Where is the microphone located in the ipad 2?

It is on the top of the iPad - above the front facing camera lense.

You can download a complete iPad User Guide here: http://manuals.info.apple.com/en/ipad_user_guide.pdf

Also, Good Instructions http://www.tcgeeks.com/how-to-use-ipad-2/

Apple - iPad - Guided Tours

http://www.apple.com/ipad/videos/

Watch the videos see all the amazing iPad apps in action. Learn how to use FaceTime, Mail, Safari, Videos, Maps, iBooks, App Store, and more.

How to - Articles & User Guides & Tutorials

http://www.iphone-mac.com/index.php/Index/howto/id/4/type/select

iPad How-Tos
http://ipod.about.com/lr/ipad_how-tos/903396/1/

You can download this guide to your iPad.

iPad User Guide for iOS 5

http://itunes.apple.com/us/book/ipad-user-guide-for-ios-5/id470308101?mt=11

 Cheers, Tom 😉