Late to this thread, but as I have the same dual-boot, I would like to add my little bit of wisdom (and so far, it IS still little - I'm a Linux newbie).
I have Windows XP Pro on my first partition and SuSE 9.0 inhabits the rest of my hard drive. On installation I chose to install GRUB bootloader in MBR. It is a lot more flexible then LILO and you can configure it to do exactly what you want. You can still install it now, it won't change your Windows installation. If you prefer to work in the SuSE GUI, find your way to "Control Centre", then to "YaST modules" (should be on top), then "Boot Loader". From there you can let YaST search your hard drive for other installations. It will find Windows XP. Otherwise you can edit GRUB to add Windows as a chainloader +1.
Another way to set up your bootloader is by installing and running Webmin. This works from GUI in your web browser. Download the rpm version from www.webmin.com
, install it and open your browser. The address is http://
Find your way to "hardware", then select GRUB and edit from there.
Should you ever wish to uninstall SuSE, you can return your MBR to its previous state by running the Windows XP setup disc and running repair or copy the NTLDR file to hard disc.
Alternatively, you can create a boot floppy in Control Centre as well - it's a nice stand-by in any case.