Hall of Explorers - This site has information on 63 explorers and includes information about the kings and queens who financed the explorations.

Notable Explorers @ FactMonster - FactMonster gives us over 50 explorer biographies.

The Mariner's Museum: Exploration through the Ages - This site has has improved a lot and has a a ton of information about 50+ explorers and their voyages as well.

Voyage of Exploration : Great Explorers - This site offers information on 28 famous explorers that includes a helpful timeline.

You Wouldn't Want to be a Polar Explorer! - Get ready…you are about to join Ernest Shackleton's expedition to icy Antarctica. Good luck!

Zoom Explorers - Lots of explorer information here. Information is divided by century.