Ever want to know which iMacs use the Intel Core i5 processor? Or which Mac models lack FireWire? EveryMac has created a very neat Web-based tool that lets you select from a wide variety of system specifications and see which Mac models match. It’s in beta, so if you see any errors or have suggestions for improvements, drop them a line. follow link
Smarter Parental Controls
If you've been using the parental controls options in Mac OS X to lock your child out of using a particular computer late at night, but would like to employ a more clever technique to limit Internet access, turn to MAC address filtering on an Apple base station.
To do this, launch AirPort Utility, select your base station, and click Manual Setup. In the Access Control view, choose Time Access to turn on MAC filtering. You'll need to enter the MAC address of the particular computer, which (in 10.5 Leopard and 10.6 Snow Leopard) you can find in the Network System Preferences pane: click AirPort in the adapter list, and click Advanced. The AirPort ID is the MAC address.
EveryMac’s Ultimate Mac Sort Tool