Hi,
I've heard that it's possible but I haven't found any procedure to do that yet. We did a MCMS-MOSS migration and we built a different set of server. I think that it's the best approach but you have to migrate all the site at one time.
The two products are very different. MOSS requiered a lot more memory (our w3wp process go over 1 gig sometimes) than MCMS. You should really think to install MOSS on a 64 bits OS to have enough memory to handle your site.
I don't know if MCMS 2002 can be install on a 64 bits OS... Also, I don't know exactly what will happen if you setup MOSS and MCMS to respond to
www.ourdomainname.com . They will fight each other to give an answer.
I'm almost sure that you will run into a long debug process.
Hope that help,
Maro
My blog (en français) :
http://spcontext.wordpress.com/