Im running a mac, and currently have bootcamp running Mac OS X Snow Leopard, And Windows 7 Ultimate 64 bit,
However I want to make a 3rd partition for Ubuntu 10.4 64 bit,
Does anyone know how to do this? or point me in the right direction?
This answer may slightly miss your question, but may be a solution to what you are trying to do.
Make sure to install Ubuntu’s bootloader onto the Ubuntu partition and make sure you update refit’s mbr table after the install is done.
I have not personally tested this method, however there is a Triple Boot tutorial for Apple hardware to triple boot with Windows and Linux. I hope this works!
I have an iMac with Mac OS X Snow Leopard and Windows 7 partitions. For Ubuntu, since I used it less frequently than OS X or Windows, I avoided the complexity and hassle of trying to set up a triple-boot Boot Camp by running Ubuntu as a virtual machine under VMWare Fusion.
If you don’t want to shell out for VMWare Fusion, you can do the same with the free Sun VirtualBox virtualization software.
A Google search for “Ubuntu virtual images” turns up a number of places where you can download pre-built Ubuntu virtual machines, making it even easier to get up and running.
I realize that doesn’t directly answer your question — which specified “via Boot Camp” — but it may provide equivalent functionality with a much lower technical threshold and less effort.