Nate,
You can and you can't. I'll explain, as I just did this yesterday.
In order to dual boot a Win9X (including ME) and 2000/XP, you need to install the Win9x/ME operating system first, and then install the XP second. Apparently, the WinME installation, if done second, really fouls up the XP boot sector and XP boot.ini file.
I did it in exactly the wrong order yesterday, and I paid the price. I have a TV card in my backup machine that I use all the time, but it is not suppored in WinXP, hence the need for WinME.
What I had to do to fix it was after I installed WinME, I re-installed XP. I just choose a "repair" installation, and it didn't mess up any of my settings, programs, etc.
That is what you are going to have to do. I even tried to use Boot Magic to dual boot when I had done the order wrong, and it couldn't even find the XP installation.
Copied from a Micro$oft document
here :
On computers that contain Windows 98 (or Windows Me) and Windows XP:
As in the cases above, Windows 98 or Windows Me must be installed on a basic disk on a partition formatted with FAT or FAT32. If Windows 98 or Windows Me is not installed on the system partition, which is almost always the first partition on the disk, the system partition must also be formatted with FAT or FAT32.
Compressed DriveSpace or DoubleSpace volumes won?t be available while you are running Windows XP. It is not necessary to uncompress DriveSpace or DoubleSpace volumes that you will access only with Windows 98.
Windows XP must be installed last. Otherwise important files needed for starting Windows XP could be overwritten.
cheers,
--jb