I cannot configure my Apple Mail to work with my Gmail account.  I repeatedly get this response, "imap.gmail.com is not responding".  Could someone please help me?  

I have tried resolving this issue several times, spent days and hours searching the internet, have read numerous forums, changed port settings, called my isp and wireless router manufacturer, and just paid for apple tech support only to be told that the issue is on my Gmail side :(

I have several Mac products that I need to get configured..

I am trying to first configure my Macbook Pro - Mac 0S X - version 10.5.8