Bino': glad to help.
Entourage, which comes with Office has newsgroups, and you will be able to subscribe to them as before.
You can "right-click" on a Mac by holding down the ctrl button as you click with the mouse.
However, if you got a new "Mighty Mouse" with your iMac G5 (it has a trackball on it), you will be able to "right-click" with that. It appears to have no buttons, but actually has four. To use the "right-click", use the area right of the trackball, without a finger on the left of the trackball at the same time.
You can set up the Mighty Mouse using System Preferences>Keyboard & Mouse. Right-clicking is referred to as "Secondary Button". You could set the other buttons to various things, for example Dashboard activation and Exposé are amongst the most popular.
AppleMacster