How does http://to./ work?
I believe that the way it works is simply who ever owns the TLD .to, simply set up an A record for the TLD itself and are providing this service.
For example, google.com and google.com. are actually the same address.
You can also access this site via http://to
Some domains use this technique to redirect you to where you can purchase domains from, this place seems to offer a free service.
Just to ensure people don't miss JMD's comment:
Many more answers at Server Fault's How the heck is http://to./ a valid domain name?