It seems as if some MacBook owners are reporting troubles with their wifi connections. I to an suffering from these problems. Here's an excerpt from AppleInsider.
System users in Apple's discussion forums (one, two), as well as those speaking directly with AppleInsider, say the problem first surfaced after the appearance of the Mac OS X 10.4.10 update this summer and so far is known to affect most models, though reports are currently scarce from buyers of Apple's fall 2007 units.The exact behavior of affected systems can vary slightly, but appears to largely be connected to the computer's power supply. While the connection remains largely stable when plugged into an AC adapter, switching to battery power renders the wireless link intermittent and in many cases drops network access entirely when idle.
On my side it even seems to mess with the speed of packet transfers too.
Hopefully there will be an update/fix soon.
