SniffPass (Freeware)
SniffPass is small freeware utility that listens to your network, capture the passwords that pass through your network adapter, and display them on the screen instantly. SniffPass can capture the passwords of the following Protocols: POP3, IMAP4, SMTP, FTP, and HTTP (basic authentication passwords). You can use this utility to recover lost Web/FTP/Email passwords.
http://www.nirsoft.net/utils/password_sniffer.html
SniffIM (Freeware)
SniffIM is a Yahoo and MSN Messenger Chat Sniffer. It tries to sniff and record all the yahoo and MSN messenger conversation going on in a network. It does this by sniffing all the ethernet traffic and then analyzing the packets for yahoo and MSN conversations. It can decode the Yahoo PM & Conference conversations and MSN IM conversations. It uses RawNetIo framework to do the core work of sniffing the packets.
SniffIM allows you to save the recorded conversations in either RTF format. It also allows you to save all the recorded messages at once in RTF format such that you can even search for important information in those conversations.
http://www.intellectualheaven.com/default.asp?BH=projects&H=SniffIM.htm