Here’s a pic of my dual Win/Mac portable web servers as seen from inside Leopard.
My dual Windows/Mac portable web server setup
I’m using Xampp for the Windows world at work and MAMP for at home on a real computer 
MAMP sits comfortably in a 500MB disk image which I just mount before using.
Database and htdocs are still being synced manually which is not the end of the world right now.