MailBell 

MailBell is a utility that checks email on POP3, POP3-SSL, IMAP, IMAP-SSL, MAPI and Hotmail-Email accounts. It can notify you of new mail, can detect undesired messages and lets you delete mail with large attachments without downloading it.
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602LAN SUITE 

Secure mail server with anti-virus & anti-spam, built-in firewall with NAT and real-time web content filter proxy for controlled Internet sharing. Access your e-mail anywhere using the included web mail client. The 5 user version is FREE.
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Mail Snoop Pro 

Mail Snoop Pro is an anti-spam and email notification application designed to monitor any number of Pop3/SSL Pop3/IMAP/SSL IMAP mailboxes, finding and deleting spam without disturbing you and alerting you when there is new mail you need to see
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