Lots of info, photos, and history. Has instruction manuals for most classic handheld games from the late 1970's to the mid 1980's. Very nice site!
Madrigal's Handhelds Simulators
Many many many handheld simulators!
Absolutely THE place to pick up used classic handheld games.
Handheld game WebRing.
Online museum dedicated to preserving vintage handheld video games from the 1970's and 80's
An inventory of handheld and tabletop electronic games. Special interest on Bambino, Bandai, Entex and Tomy games.
Clint's Handheld Web Page
All sorts of handheld game information and pictures.
Game In Hand
Retro, vintage, electronic games from the past. Nintendo Game and Watch Games, Bandai, Casio, Coleco, Epoch, Entex, Gakken, Mattel, and Tomy.
Vintage Gaming Network
Lots of vintage gaming stuff of every kind, although their handheld section seems to have fallen into disrepair lately...
Classic arcade game emulation. Usually not handheld related but still cool.
Handheld Mania offers a nostalgic look at some of the greatest handheld games of the last 25 years.
USENET group for classic gaming. Usually a lot of handheld posts.