I would install winxp on the second HD(or partition) and then run linux install. most newer linux will detect your XP and put it in a boot menu using Lilo bootmanager.
Make sure u have some space on ur harddrive for linux. Linux needs 3 partitions but u can create them during linux install. U can use partitionmagic to set the linux boot partition to active and u can delete or resize some partitions before u install linux to make some space.
i am not a linux specialist but i am sure u need to install XP first because Xp will not recognise linux.
ur active linux boot partition needs to be set as primary boot device in your BIOS.
u probably don't need to do lots of settings...i would say just install Xp and then linux and mostly it will work automatically.
TheMajorMMX - Intel P200 MMX @ 225Mhz - V-Tech (PcPartner) Baby-AT mb w/ Intel Triton TX chipset - Nvidia Riva TNT2 M64 w/ 16MB - 256MB M-Tec SDRAM - Still running.....