Apple's Airport is a very reasonably priced wireless access point, however, it does not have provision for connecting an external antenna. This is easily remedied if you don't mind voiding your warrantee. The results look like the photo below. The benefits of adding an external antenna are much greater range. We found a 6 db gain omni antenna gave 10 to 20 db improvement in signal to noise ratio. This theoretically should improve the range by more than three times in free space. This is even more than Lucent claims.
The Lucent Wavelan card used in the airport has an antenna connector on it. It just isn't accessible in the airport. All you need to do is take your airport apart, and carve a place for your fingers to fit as you plug in your external antenna.
The first step is to remove the bottom cover using a Phillips screwdriver.
The next step is to remove the guts of the airport. You will have to disconnect the internal power and 10BaseT connectors.
The next step is to use your Dremel tool to carve out a place for your fingers so you can insert and remove the antenna.
The next thing you need to do is remove the little black plug over the antenna connector on the end of the Lucent Wavelan PCMCIA card. It is shown below removed to reveal the female antenna connector you will plug the antenna into.
Here is a better view of the finished modification.
Antennas are available from Hyperlink Technologies, and others. The connector you need is called an MC card plug. Be careful inserting it. These connectors are only rated for several hundred insertion cycles. You can also roll your own. Instructions on using a surplus Primestar dish are available here.
This modification surely voids your warrantee, and it is possible you could break something by doing it, so I disclaim any liability resulting from these modifications.
My thanks to Seth McNeil who actually made the modifications on this airport.