In an article entitled Apple’s missed opportunity, a certain Paul Jackson from Forrester Research has this to say about the new G5 iMac:
"Better still would have been a software option to turn this machine into a full Wi-Fi access point: Intel’s Grantsdale chipset already promises this functionality for PC owners. The lack of this connectivity means that Apple has missed an opportunity to build on its AirPort Express foundations and rule the roost in bottom-up networking."
Paul, go to Systems Preferences -> Sharing -> Internet and click on that big "Start" button.
The small print at the end of the article states:
"Information is based on best available resources."
Forrester, you’ve got some lousy resources.