Capone celebrating Mr. Darwin's birthday.
Today, February 12, 2009, is the 200th anniversary of the birth of Charles Darwin. To mark the birth of this landmark scientist and thinker, celebrations are being held around the world. Are there any near you? You can find out at the Darwin Day Celebration site. Interesting information about Darwin and his theory is also available there.
Would it be rude to mention Alfred Russel Wallace on this, Darwin’s special day? Wallace was credited as the co-discoverer of evolutionary theory, but has never attained the fame of Darwin. Wallace corresponded with Darwin about his theories and it is likely that he played a role in Darwin’s decision to “go public” with his views. Born into more modest circumstances than Darwin, Wallace enjoyed neither his social status nor scientific credibility. He developed his theory while doing field work in the Malay archipelago, where his name lives on in Wallace’s Line, the boundary that separates the zoogeographical regions of Asia and Australia.
A highly enjoyable account of Wallace is given in David Quammen’s Song of the Dodo. Subtitled Island Biogeography In An Age Of Extinctions, Quammen weaves Wallace’s story into his fascinating and frightening examination of extinction and fragmentation.
Willow House Chronicles 
If memory serves me right, I think Darwin had the idea 15-20 years before Wallace, but never published … and it was Wallace who coined the phrase Darwinian.
Afrankangle, it’s been a few years since I read up on this topic. My memory is that, as you say, Darwin had the idea for a while but hung back from publishing because of the reaction he knew it would provoke. Not sure of the exact timeline. Wallace did write a book in 1889 entitled Darwinism, explaining and defending the theory.