This is a one-page review of the introductory issues regarding the Book of Acts. It includes a lengthy section on the debate concerning the authorship of Acts.
This is the online version of the well-known Catholic Encyclopedia. Though somewhat dated, the article still gives a very clear, accessible introduction to Acts. It is also heavily hypertexted, allowing the reader to explore other issues elsewhere in the encyclopedia.
Although this Web site is geared toward providing informed resources for Christian preachers, the lists of Scripture passages in these tables are linked to rich lists of resources from all around the web. This is an excellent site for finding what relates to a particular Scripture passage.