I thought I'd use the Where Did I Park My Car web app I wrote to record the location of the car park to make it easier for others to find the car park. There's two exists as you approach Melbourne Airport. One for terminal 4 which is the first exit, and the other exit for terminals 1, 2 and 3, which is the second exit. Every time I visit the airport things seem to change and this time was really the first time I'd used the exit for terminal 4.
The location of the Ring & Ride car park you can find using the link http://maps.apple.com/maps?q=-37.681654304397526,144.8650513606828.
The car park rates are:
20 minutes free
21-40 minutes $2
41-60 minutes $4
If you need to pick up someone at Melbourne Airport, knowing about the free Ring & Ride parking can certainly be useful.