k9mail for Android with OpenPGP support
Version 3.0 of the free k9mail Android email client, often simply referred to as K-9, is the first to support the in line encryption and decryption of emails via PGP and can verify digital signatures using the free Android Privacy Guard (APG) OpenPGP implementation. Both k9mail and APG are available to download from the Android Market free of charge. Additionally, k9mail features better IMAP support than the original Android email client.
The k9mail developers have also implemented other new functions and improvements. For instance, users can now choose a sender identity from any of their accounts, individual accounts can be reached via short cuts and the user interface offers dedicated buttons for the "archive" and "spam" folders.