Topics in Islam
General
History
http://www.islamicity.com/education/ihame/default.asp?Destination=/education/ihame/1.asp
Basic sources
Quran
Including text, tafsir, recitation.
note: some of these sites are up and down....if it's not working try another, or search....
http://www.islamicity.com/mosque/quran/
http://www.islamicity.org/quransearch/
Hadith
http://www.searchtruth.com/hadith_books.php
http://www.usc.edu/org/cmje/religious-texts/hadith/
http://sunnah.com/ (you can search using Arabic as well here)
http://www.sacred-texts.com/isl/hadith/index.htm
Tafsir
Fiqh (law)
Kalam (theology)
Sira (Prophet's biography)
http://www.al-islam.org/life-muhammad-prophet-sayyid-saeed-akhtar-rizvi (by a Muslim)
http://www.faithfreedom.org/Articles/sira/index.htm (by an anti-Muslim!)
Tasawwuf (mysticism)
Falsafah (philosophy)
http://www.muslimphilosophy.com/
Ritual practice (Islam)
Shahada
Salah
Sawm
Zakah
Hajj
http://www.islamicity.org/7758/hajj-walking-the-walk/
Adhan
http://islamcan.com/audio/adhan/index.shtml#.VowMMpMrJE4
Tilawa
See under "Qur'an" above.
Audio, general
http://www.sfhbukhari.co.uk/Islamic_Audios.html