Today's 10.5.2 update to Mac OS X seems to have solved my issue of losing wireless connectivity every half-hour and having to reboot to get it back. I was about ready to throw my laptop out of the window with this one. How was I supposed to get work done when the internet was constantly going away?
I wasn't sure how much more I could have taken before I just installed Linux on this box to get back to work.
So thank you Apple for saving my laptop. And thank you for not making me go through the pain of dealing with a dual-boot Linux box once again.