go to the Network System preferences pane.
At the bottom of the window where you expect the Airport to appear, there is a "+" & a "-" sign
Click the + sign.
You may have to supply and Admin password to unlock the preference pane.
You should get a drop down that asks you to select the interface.
It probably says Airport already, but if it doesn't, use the dropdown arrows at the end of the Interface field.
Choose Airport, put a name, Airport, in the Service name field and click Create.
You should now have an Airport interface in the left hand window.
Let us know how you got on
I recently got a new HD and RAM for a friend's 2007 MacBook 2GHz and firewired everything over from an iBook running Tiger after installing Snow Leopard [and updating everything] on the 2007 Macbook. Everything seems fine except Airport doesn't show up at all in Network Preferences: I get the little greyed out Airport icon in the menu bar clicking on it produces a drop down list that reads "airport is not configured" and below that "Network Preferences". Clicking on "Network Preferences" opens the appropriate system preferences but again there is no airport option anywhere. I can connect via ethernet. Airport was working using the previous HD and show up as present when I check System Profiler. Is there a way I can totally remove and start over with the Network Preferences without clean installing? Or any other suggestions would be much appreciated?