Phonology

• Rutgers Optimality Archive: Outlet of research papers in Optimality Theory.
• Bruce Hayes' OT software: If you're tired of ranking constraints and drawing tableaux...
• IPA fonts: Yamada Language Center's links to phonetic fonts.
• SIGMORPHON: Information on computational morphology and phonology including links to programs and bibliographies.
• Metathesis: A research project page devoted to this interesting phemonenon.
• Dani Byrd's link list: An extensive collection of links related to phonetics and speech science.

Language acquisition

• CHILDES: Database and analysis tools for child language, including bilingual and impaired data.
• Talkbank: CHAT and MP3 learner corpora of older children and adults.
• Steven Weinberger's Foreign Accent Archive: Recorded speech samples of second language English with an impressive range of native language backgrounds.

Others

• Ethnologue: An on-line compendium of the world's languages plus other web resources.
• ARC nonword database: Need some nonwords?
• The Whole Brain Atlas: Tons of neuroimaging of the human brain.