08.06
Apple released the 10.5.8 update last night. Usually I wait about a week to apply any core updated but since 10.5.8 was released as minor update with some improvements to the airport wireless, I did not see any harm in updating. As of this morning, my wireless performance while on battery “SUCKS”. The moment you plug in your power supply, the network performance increases dramatically.
Ping first on battery and in the middle of the test I plug in the adapter and then I unplug the external power.

So what gives? On battery I get anywhere form 300ms to 1000ms ping times and around 70ms while connected to external power. I have contacted apple and looks like most of the macbooks affected are from 2008 but no one sure. There is thread on apple forums where few people have posted similar issues. http://discussions.apple.com/thread.jspa?threadID=2106968&tstart=0
On a side note, I noticed that apple censored the word “SUCKS” from my discussion post. They replaced sucks with *****. It looks like I said “s**** or f**k” rather than sucks. Nice going Apple. Morons. Is sucks offensive?

I discovered this too; anything we can do about it?
Harrison,
Apple has issued a fix to this couple of weeks ago. If you do a apple > software update, you should see the patch for this.
Hope this helps.