C# Monitor all TCP traffic for HTTP, HTTPS, POP3, SMTP, IM, etc.

We? need an exe written in C# that will run as a server to monitor TCP traffic for HTTPS, SMTP, POP3 or Instant Message headers (MSN, Yahoo, ICQ, etc. all the popular chat programs). This C# program must be written as efficiently as possible, without using much CPU or RAM. This piece is for a monitoring program that will watch to see if children are surfing for p0rn or writing about things in chat that they should not be (such as giving out their phone number, address, etc.).