xip.io: wildcard DNS for everyone

xip.io is a magic domain name that provides wildcard DNS
for any IP address. Say your LAN IP address is 10.0.0.1.
Using xip.io,

          10.0.0.1.xip.io   resolves to   10.0.0.1
      www.10.0.0.1.xip.io   resolves to   10.0.0.1
   mysite.10.0.0.1.xip.io   resolves to   10.0.0.1
  foo.bar.10.0.0.1.xip.io   resolves to   10.0.0.1

...and so on. You can use these domains to access virtual
hosts on your development web server from devices on your
local network, like iPads, iPhones, and other computers.
No configuration required!
    

How does it work?
xip.io runs a custom DNS server on the public Internet.
When your computer looks up a xip.io domain, the xip.io
DNS server extracts the IP address from the domain and
sends it back in the response.
    

Does xip.io cost anything?
Nope! xip.io is a free service from 37signals, the
creators of Pow. We were tired of jumping through hoops
to test our apps on other devices and decided to solve
the problem once and for all.