How can i tell my e-file for extension was received? I was able to print out the 4868 but didn't get any e-mail or phone confirmation.

To confirm receipt, it's easiest if you use software like TurboTax Easy Extension, since you'll get a confirmation from TurboTax within 48 hours. No confirmation will be provided if you use a paper Form 4868 to request an extension and send it through the U.S. mail or an authorized private delivery service.