York is a simple network capture tool which can log and analyse the traffic on your chosen network interface.
As with many similar tools, the program works by using WinPcap to log network traffic. Unusually, though, you don't have to find, download or configure this yourself: York will install it for you.
You do still have to set up the network adapter you'd like it to log, as this isn't decided automatically. But that only takes a moment (click Options > Network Adapter and choose the one you'd like to be monitored).
And once the program is configured, it can display your traffic details in all kinds of ways. The Packets view shows you the basic details of each connection: the local and destination addresses, ports and packet size. York can also capture the files you access and the pictures you view. And the program even detects HTTP, FTP, POP3, SMTP, SMB, VNC and AIM passwords, very useful if, say, you've forgotten an email account password and your email client offers no way to display it.
Version 1.61 includes the latest version of WinPcap.