There isn't an official biography for Band Aid on AllMusic.com but I'll briefly tell you what I know.
Sometime in late 1984, Bob Geldof (of the Boomtown Rats) watched a television program about African famine. He was so stirred by the footage that he wanted to make a charity record, with all proceeds going to famine relief.
After writing the song with Midge Ure (of Ultravox), he was able to get a lineup of the top English artists of the time to participate.
Their one release "Do They Know It's Christmas Time" was reportedly the biggest selling single in British history for a while. There was also a 'making of the video' film that was broadcast. The singles striking collage cover art was created by reknowned artist Peter Blake, creator of the legendary "Sgt. Pepper" album cover.
This song prompted an American response in 1985. Their group was spearheaded by Michael Jackson and Quincy Jones and called "USA For Africa." They released a single called "We Are The World" which was highly successful and culminated in the massive "Live Aid" concerts in July of 1985.