Edit 06/04/04: TML3 released:
TML3 adds 6 tribes, 10 civilization advances, 6 new buildings, 17 new wonders, 4 new resources, 2 new governments and 20 new units.
The Missing Links is available from CCJ39's homepage here:
http://www.ccj39.com/civ3modpacks.php
His page includes screenshots and a .txt description of all the features added.
Enjoy !
AK.