file sharing with win 7 and xp question

can anyone point me to a thread or FAQ on the easiest method of sharing my files from my evernal HD connected to win7 with my computers connected to xp.
my main pc is running win7 and has an external HD with all my documents and I want to share them with my laptop and netbook that are both running XP

BTW there is a bit of a learning curve going from xp to 7 I'm finding it hard to figure out how to adjust some settings. or rather where to go to adjust them

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