the actual reasons for al-qaeda's formation actually aren't anything to do with bin laden but his right hand man and the founder of the organisation al zawhirri (i know i might have spelt his name wrong). he's a very strong islamist and was involved in the iranian revolution and wanted to see the rest of the middle east follow suit. he tried in many countries and they ended in bloody failure and he retired to afghanistan (where he would later met bin laden). there it occured to him that it might be a better idea to impress the muslim world, this resulted in the attacks in africa.

there was a show here which documented the emergence of al-qaeda and the way in which they have been presented as a threat. if i can find a link to it i'll post it here. (apoligies in advance if i double post to give the link)