Have you tried Wubi?
I can't speak from personal experience (Debian man myself), but I've been told it's a good way to install Ubuntu, which does all the partitioning for you and works around your Win XP install without interfering with it. I'd recommend having a good read of the Wubi website before trying it, but it might be an easier/safer option than trying to partition everything by hand.
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Wed 14 May 2008, 13:39,
archived)