Branching projects

Hi, I want to spin up a major rework of my vs2005 website but keep it around
for maintenance during development. Best I think would be to copy the code
to a new folder, rename, create a new website and check it in as a new
project, I'm using VSS 6.0. But obstacles abound.

How do you suggest I do this? Where do I look for clashes? for example I
notice GUIDs in the .sln, I assume these should be manually regenerated when
creating the new project, or can VS do this for me?

Thanks, CoffeeGuy