Greatmail works on all POP3 and IMAP compatible devices.  Additionally, all accounts at Greatmail work using both protocols; you can configure an account using both POP3 and IMAP on different devices or computers. Connecting mobile devices to Greatmail simply requires that the device support either POP3 or IMAP. This includes but is not limited to iOS (iPhone and iPad), Blackberry, Android and Windows Mobile devices.