[boost] [database] - guid class

I can not find a guid/uuid class. Is there a guid/uuid class out there? I develop with Windows and found the strut GUID in <guiddef.h>, but I am looking for a class that has the member functions one would expect with a value class (ie comparison, equality, ...). I created a simple guid class and I am wondering if any one else would find it useful. I have read on this list about a proposed database library and I believe that it should have a guid class. Andy Tompkins