Learning the hard way...
...to read before doing.
Having had several interchanges with Robert McLaws on the issue of wireless network security, I thought it might be a good idea to see if my wireless router manufacturer had gotten around to releasing new firmware with WPA (Wi-Fi Protected Access), as promised in the product sheet. Indeed, they had. So, great, I download the file, noting that it says it's for hardware revision B only. My rev. is A, so I check the support site, and the download page there doesn't have the note about B, so I figure perhaps the other page is in error...first mistake.
Second mistake is to not read the instructions in the FAQ for installing firmware, which states loud and clear that you SHOULD NOT UPDATE FIRMWARE VIA A WIRELESS CONNECTION!
So what do I do? Of course...I install the wrong firmware, via a wireless connection. D'OH! Next thing I know, my router's wireless portion is completely hosed, and the router is re-booting itself every 5-10 seconds or so, so it's nearly impossible to get into the admin interface long enough to try to fix the problem.
Well, to make a long story short (too late :-) ), after spending more than a half an hour messing with the admin interface, I managed to downgrade to the original firmware that came with the router. That still didn't solve the re-booting problem, so I unplugged the router, and held in the reset button while powering it back up. That managed to get the re-booting to stop, and the wireless portion of the router came back online.
Fortunately, I still had a copy of the last good firmware, and had saved the router settings to the filesystem of my laptop prior to trying the newest firmware, so I was able to get back to where I started. But I hope that my experience will be a lesson to you all. Read the FAQs, or suffer the consequences. Fortunately, mine only amounted to a few lost hours, but it could have been worse.