1. No, email only.
2. No, it is not.
OWA integration with BIS is "better" than POP/IMAP in that is offers tighter integration and more wireless reconciliation features from handheld to mailbox. While not officially documented, you may also notice faster push with OWA integration over POP/IMAP.
KB05133 - Email reconciliation features for the BlackBerry Internet Service - Port3101.org : Your BES Connection