The human ancestor, Australopithecus afarensis, is best known for the specimen, Lucy. It lived in East Africa between 3.8 and 3.0 million years ago. In Hadar, Ethiopia, scientists have just discovered a 3.2 million year old foot bone of the species establishing that it had arched feet and, therefore, was completely bipedal. The findings have been published in the 2/11/11 edition of the journal, Science.
Lucy is not our oldest missing link, am I right? There is a handful of partial afro-india finds, a chinease guy with hemp, and some indo europeans? I think :search: Julian Jaymes did a butt load of research on proto-man. Prior to missing link finds such as Lucy and etc.
There are older Hominids than Lucy. If you look far enough down in Joan's very informative 'Evolutionary Trees' post you will see them in a schematic that documents the evolution of Hominids from them to Homo sapiens. Fossil evidence of Hominids older than Lucy has thus far only been found in Africa.