PacketStream for Mac

From Kevin Walzer:

PacketStream provides point-and-click activation of the Mac's built-in network monitoring program, which is usually available only from the command line. By clicking a few buttons, you can monitor data as it streams over your network--especially useful for checking web traffic, network bottlenecks, or even suspicious network activity. All network data is displayed in the application itself, and you can save the data to a file for further analysis later. PacketStream provides a user-friendly way to configure and use the Mac's network monitoring tools. It is easier than typing in cryptic commands in Terminal. As a native Aqua application, it is more intuitive to use than complex, hard-to-install, Unix-based GUI programs. And it is simpler than more expensive "swiss army knife" network programs, which are overkill for most users.