Newapocrypha	A wiki fan site that covers everything Doctor Who related, from the show itself to roleplaying games. While it works toward continuity, it does not pretend to give any authoritative answers on "canon." (Personally, I prefer it that way.)
Wikipedia	Geeks like us just love to share our knowledge, so this general-info site is loaded with goodies, including the details of most episodes and novels.
Rassilon, Omega, and that Other Guy	A very extensive fan site, carefully and legibly cited as to whether the info came from the show, novels, etc, but with a serious need for proofreading (only a problem if you're picky about spelling and grammar!).
Whoniverse	Another fan site, also very good, although it has a pretty serious bias in the opposite direction as mine.

Amica Temporis is Latin for 'time's friend,' specifically 'time's female friend,' with the potential implication of 'girlfriend' or mistress,' and is therefore the perfect term for most of the Doctor's companions. Read my manifesto.