I recently finished some how-to's for getting Ruby, Ruby-On-Rails, RVM, Rack and Passenger integrated into the XAMPP environment. For those that have an interest in a portable LAMP stack w/integrated Ruby you can read about them here:
How-To: Add Ruby-on-Rails to XAMPP http://www.apachefriends.org/f/viewtopic.php?f=17&t=43516
How-To: Add Ruby RVM, Rack and Passenger(mod_rails) to XAMPP http://www.apachefriends.org/f/viewtopic.php?f=17&t=43536
Regards, Gerry