Here is the list of some helpful links regarding IMAP and POP3 protocols in Exchange 2010:
Enable IMAP4 in Exchange 2010
Enable POP3 in Exchange 2010
Managing POP3 and IMAP4 in Exchange 2010
Understanding POP3 and IMAP4
Public folders and IMAP
Accessing shared and delegated mailboxes
Tags: Exchange IMAP POP3