BBC NEWS | Science & Environment | Fossil finds extend human story
discusses the announcement of Ardipithecus ramidus, a early hominid ancestor with many characteristics of both humans and chimpanzees. It has taken 17 years of study to put the fossils in the correct context, but that is how science works - carefully, meticulously, building upon prior work.
UPDATE: This is a really good article from Science, discussing how the Ardi find fits in with the Lucy discovery in 1974. In a nutshell, Lucy showed us that early hominids walked upright, while Ardi showed that even earlier hominid precursors also had a form of upright walking, while also spending time in tress.