What is the best way to transfer an email address (please see details)?

I currently have at%26amp;t DSL and use their email address. I am discontinuing the service and having the Comcast Triple Play installed. I have given my email to over 50 websites and hundreds of people. What is the best way to go about transffering to the new email? Can I have the Comcast email now before they install it?|||ISP email goes with the account. You'll get Comcast email once they install it and you'll lose AT%26amp;T email once the account is canceled. That's why you should use a 3rd party email address like Yahoo or Gmail.