I dunno really Iron... the only thing I can imagine is that the current magnetic fields simply won't exist while the poles move... or will be severly altered...
You know how it is right now...

When the two poles reverse... dunno how they do it... I'd assume that the field would significantly change or shrink in size while the poles change position.
The article mentions deadspots in the Earth that have started to occur recently and are getting bigger... this is saying to me that the poles aren't staying perfectly opposite one another, and may be changing position in such a way that it's not a simple flip, but instead are maybe moving through each other? (I dunno if that's even possible... but this isn't necessarily two solid magnetic objects acting against each other either.. but is a single fluid
source)
EDIT: Here's another article from Nov 10, 2002:
http://www.observer.co.uk/international/story/0,6903,837058,00.htmlEDIT #2: This is a pretty good read:
http://www.psc.edu/science/Glatzmaier/glatzmaier.htmlEDIT #3: Seems most sources agree that while the magnetic field is getting weaker, the reverse/flip won't happen for another thousand years or more...
-SW