I have had this Airport base for a few years and, since upgrading to Mac OS 10.5 (Leopard), the included Airport Utility has never recognize my base. I had tried whatever I could think of to no avail. At last I have tried googling stuff like "airport base Leopard" and finally have found the solution on this Apple forum.
This brilliant guy came up with this smart suggestion for installing the old version of Airport Utility called Airport Admin Utility that recognizes my base so that I can administer it from my MacBookPro. As someone else says on that thread:
"It's times like these I really love the internet. Thank you, Larry! "
...on the other hand a snow leopard is a completely different story.

UPDATE: I sold it and got an Aiport Extreme.