3-D Starmaps contains the formulas I used in the Internet Stellar Database for calculating distances between stars.
Richard Powell has a page on Anzwers.org with a 3-D visual map of Stars within 20 light years of the Sun.
The Extrasolar Planets Encyclopedia contains frequently-updated information on planets discovered outside our solar system. So, for that matter, does EXOPLANETS.
exoplanets.info is another extrasolar planets reference site, more recent than the above two endeavors. It makes an effort at being complete, and has probably the most comprehensive information lists on each individual extrasolar planet of any of these sites.
Part 7 of the sci.astro FAQ contains information similar to that found in the main articles accessible from the Internet Stellar Database's main page, but in greater detail.
NearBy Star Observers is, in the words of its homepage, "An Organization that is active in Observing, Studying and the Exchange of Information of the Nearby Stars within a 20 parsec (65.2 light year) radius of the Sun." Their pages come in English, German, Spanish, and French flavors. The latest edition of their newsletter and some of their data appear directly on their website, and access to their better goodies comes with membership (which is now free).
The Research Consortium on Nearby Stars (RECONS) collects observational data, and has even been responsible for improving the accuracy of the parallax measurements to some of our stellar neighbors.
Long Way Down the Road is a self-described "white paper discussing the astronomical possibilities of life-bearing planets within the 'immediate' stellar neighborhood". NOTE: As of April 2001, this webpage appears to be defunct, so I have archived it here.
The Astronomisches Rechen-Institut Catalog of Nearby Stars contains information from the top secret 1998 revision of the Gliese catalog, which I simply haven't been able to get my hands on. It includes V-R color index information that I don't have, too. Not that I'm bitter.
Professor Jim Kaler has a rather substantial page simply called Stars. It contains details on 210 stars, many (if not most) of them too far away to merit inclusion in the Internet Stellar Database. It also has pretty pictures.
Kurt Foge wrote a book titled 3-D Star Maps, which seemed to have been inspired by the same sorts of ideas that inspired the Internet Stellar Database, and included instructions on how to build 3D stellaria. The first two sample pages used to be available online, but his website no longer exists. An archived copy of the book's webpage can still be viewed at http://web.archive.org/web/20100221062157/http://www.kurtfoge.com/book_contents.html.
New Scientist magazine has an online article by Ken Croswell about the chance for life-bearing planets around red dwarfs.