http://www.geocities.com/p.pals/penpals.html

General
PenPal Garden -- A place for make friends
Interpals Penpal Net
Penpal International

Kids
Kid Connect Penpal Box

Japanese
Japan penpals
Japanese Penpal net
Japanese Penpals
Japanese penpal Board

Language Exchange
International Penpals - Email Exchange of Language and Cultures

German
brief-freunde.de - Brieffreunde suchen und finden
penpal-pinboard.de find free international mailfriends and penpals from all over the world.