Here are some links to help you in your research for your presentation. Not every composer is available at every link, but if you look around there will be sufficient information about each person.
Chapter from a music history book
A site to get specifics about individual shows
The sources at the bottom are the most interesting part of this
A college course lecture on musical theatre
Internet Broadway Database (which is like IMDB, but for Broadway)
As always, Wikipedia is a good starting place, with valuable sources. DO NOT SITE WIKIPEDIA ITSELF. It is not reliable as a source.