In terminal bring up the grub prompt and as root

grub

root (hd0,0)

setup (hd0)

Did you try using the map first then the rootnoverify, like alan ri suggested?

title Windows XP
map (hd0) (hd1)
map (hd1) (hd0)
rootnoverify (hd0,1)
makeactive
chainloader +1

But, if that doesn't work, I'd try using a grub boot floppy to reinstall grub. It is not clear to me if grub is installed in both MBRs (it sounds like it is on the linux disk not the windows disk) and where grub is looking for the menu.lst. Use the find command at the grub boot prompt using a grub boot floppy to find out where it thinks the files are.

My other piece of advice is: stop swapping the drives. Install the Windows drive as the master, the linux as the slave and leave it like that. Install grub to the MBR of the windows XP master and let grub find its files on the slave on the reinstall from the boot disk. Make sure the system is booting off of the correct disk in the BIOS. Sometimes you have to wipe grub off of the MBR (with FIXMBR or dd and a saved copy of the MBR)on both drives before reinstalling, not sure why... You did save a copy of the MBR, right?

Hope this helps. I'm not an expert: I just seem to have made nearly every boot mistake before!

Ok I'm guessing when you installed linux you had the hard drive with windows on it unpluged. The reason I say that is in your OP you said you could plug each OS into the 0 plug and it would boot.
Here is what I would do, plug in the drive with windows on it into the 0 spot so you can boot to it normal, and plug in the linux drive in the NO, 1 sata spot. Now go into your bios and to the boot option and set the linux drive first in boot order. Once you have this done save and exit the bios. When your system reboots and gets to the Grub screen, press c for command line, now edit the entry I have high-lighted start with (hd0,0) and work your way up like so (hd1,0) (hd2,0) ext.

When you find the one that works, boot into linux and edit your /boot/grub/menu.lst to make things permanent.
I have a similar setup to yours only my windows is on a raid0 array, so I had to map to the first drive in the array. My menu.lst looks like this,

ok thanks to mrrangerman, I went into my setup menu and while I was looking around, I realized that SATA 1 port was off. I turned it on and put in the original suggestion by alan_ri and it worked right away. Thanks a lot for all the help everyone. Btw, master drive is linux, windows is slave.