how do I run windows on mac mountain lion?

You can only run XP by using virtualization software:

Windows on Intel Macs Using Virtualization Software

1. Parallels Desktop for Mac and Windows XP, Vista Business,

Vista Ultimate, or Windows 7. Parallels is software

virtualization that enables running Windows concurrently

with OS X.

2. VM Fusionand Windows XP, Vista Business, Vista Ultimate,

or Windows 7. VM Fusion is software virtualization that

enables running Windows concurrently with OS X.

3. VirtualBox is an Open Source freeware virtual machine such

as VM Fusion and Parallels that was developed by Solaris.

It is not as fully developed for the Mac as Parallels and VM

Fusion.

Note that VirtualBox, Parallels, and VM Fusion can also run other operating systems such as Linux, Unix, OS/2, Solaris, etc. There are performance differences between dual-boot systems and virtualization. The latter tend to be a little slower (not much) and do not provide the video performance of the dual-boot system. See MacTech.com's Virtualization Benchmarking for comparisons of Boot Camp, Parallels, and VM Fusion. Boot Camp is only available with Leopard or Snow Leopard. Except for Crossover and a couple of similar alternatives like DarWine you must have a valid installer disc for Windows.

You must also have an internal optical drive for installing Windows. Windows cannot be installed from an external optical drive.

Isn't there a workaround?

Like downgrading BootCamp and or creating an empty FAT partition and then installing Windows XP into it and then putting drivers in place?

To follow up on Kappies post. Only using Boot Camp do you need a Windows install DVD, that is unless you have a Mac that does not have a DVD drive then you can use a USB thumb with the Windows install file loaded on it.

Also Boot Camp is a MOTE point as you can only install Win 7 using Boot Camp.

For XP you must use a Virtual Machine program and to install XP into a VM you can use either a CD/DVD disc or an ISO file.

Apple stopped supporting installing XP into Boot Camp with the release of Lion.

Have a look at this video