Just burn everything to disc then you know you have it, that is the fool prof way. If you try to make a partition and mess it up say bye bye to your stuff. If you have a home network just transfer them to one of the other systems untill the format is done.
As far as formatting goes, boot into the bios and make sure your cd drive is set as the first boot device then just boot from the xp cd and follow the onscreen instructions. delete all the partitions (after you have made back ups of course) select the unpartitioned space and format it with nfts(quick) and sit back and have a beer.