A mailing list and website for linguists, The Linguist List provides information on language and linguistic analysis. The site hosts archives of more than 100 additional linguistics mailing lists and contains a database of language and language-family information and recommendations for digitizing data on endangered languages.
Linguistic Resources on the Internet
This page from SIL (Summer Institute of Linguistics) International bills itself as "a topically organized list of resources elsewhere on the Internet that may be of interest to the linguist." Covers the principal categories of linguistic research.
Ethnologue: Languages of the World
Online edition allows one to find information regarding geographic distribution of languages, languages of special interest, nearly extinct languages, etc. Browse by language name, language family, or country name. Includes maps.