If you have a good backup(read copies) of all your data, and can verify that you can access them, then what you want to do is safe. If you do not have a good backup, then it is not safe - whatever.
I was wondering , I have a lot of stuff on my 100 GB hard drive. And I want to make a dual boot system with Windows XP ( now installed ) and Linux Ubuntu. But can I make 1 or 2 partitions on my harddrive WITHOUT losing the data dat I have now? And without damagaing Windows XP? And then just install Linux on a partition. Is there a safe way to do this?