Listen to this musical tribute to Clyde Tombaugh and the New Horizons mission:
http://www.eliasfey.com/newhorizons.html

NASA New Horizons Site
http://www.nasa.gov/mission_pages/newhorizons/main/index.html

New Horizons Science Team site (Southwest Research Institute)
http://www.boulder.swri.edu/pkb/

Great information about Pluto (Lowell Observatory)
http://www.lowell.edu/users/buie/pluto/pluto.html

Welcome to the Planets (JPL)
http://pds.jpl.nasa.gov/planets/welcome/pluto.htm

NASA Solar System Exploration: Pluto
http://solarsystem.nasa.gov/planets/profile.cfm?Object=Pluto

The Space Place
http://spaceplace.jpl.nasa.gov/pluto

Names of the planets in other languages:
http://www.nineplanets.org/days.html

Lowell Observatory, where Clyde Tombaugh discovered Pluto
http://www.lowell.edu/

Clyde Tombaugh site
http://www.klx.com/clyde/index.html

NASA Deep Space Network
http://deepspace.jpl.nasa.gov/dsn/