Yes. If you look at the www.tldp.org
website, there will be some howto's on how to do it. You will want to update lilo or grub on one of the two distro's do that you don't get a case of the dueling distro's. You could also use the same /home partition for both distro's. If you use different user names, there should be no conflicts. Bear in mind that Mandrake starts the UIDs at 500 while SuSE uses a different range.
One way to do it is to use the root partition, rather than the MBR, for lilo or grub on the second distro, and have the first distro chainload the second's boot loader. This will have the disadvantage of going through two boot menu's to start the second distro, but this way, you can update lilo/grub on the second distro normally, making it easier to maintain.
Another way would be to use the XP's NTLDR to chain load whichever Linux distro that you want. There are numerous messages on this site on how to do this (use the search function) as well as numerous how-tos on the Net (use google).