It's too hard to keep up to date on all the individual Roguelike pages out there, so I've included a list of my most highly recommended starting points. These are pages to which I turn when I want to find info about specific Roguelike games or Roguelikes in general. Enjoy!

Last checked: 2011-06-20

Site / Page Maintainer Last Updated My Comments
General Roguelike Sites
Roguelike Basin Petri Kuittinen 2011-06-19 This wiki is a great starting point. It seems to be keeping up with the latest releases.
Temple of the Roguelike Santiago Zapata 2011-04-08 Lots of reviews of roguelikes, with particularly in-depth coverage of the annual 7-day roguelike challenges.
@Play John Harris 2011-03-20 Long series of lengthy articles about roguelikes. Very well written!
Home of the Underdogs Sarinee Achavanuntakul 2005 HOTU is a super-popular abandonware mecca, even thought it hasn't been updated in years. I've linked to a Roguelike-dedicated page which provides lots of reviews and downloads.
Roguelikes for Palm OS i0lanthe 2006 You can play Rogue, Larn, and Moria on your Palm Pilot!
Roguelike Roundup K. Paul Mallasch 2004 One page of quick reviews of all major Roguelikes, with a "favorite Roguelikes" survey. (newsgroup) (daily) One of several discussion groups devoted to Roguelike games. Recommended as long as you don't mind wading through chaotic chatter and sporatic spoilers.
Sites for Specific Roguelikes
The NetHack Index Dion Nicolaas 2005 A ton of NetHack links with verbose descriptions and author names. I liked the format so much I decided to mimic parts of it here!
Thangorodrim (Angband) Robert Ruhlmann 2006 Robert has an excellent set of Angband pages, and was also the maintainer of the popular Zangband variant for years.