The Stanford Encyclopedia of Philosophy

Jim Pryor's guidelines on writing a philosophy paper

John Perry's advice for procrastinators

Søren Kierkegaard Forskningscenteret (with Kierkegaard's entire corpus in a searchable online database)

Intelex past masters (with many other historical texts, in searchable form - you have to be signed in through the Cornell library)

Hathitrust (scans of many historical texts not available from Intelex, with limited search functionality - sign in by choosing Cornell as your host institution)

Deutsches Textarchiv (another database of scanned texts, with some search functionality)

Digitale Bibliothek deutsche Klassiker (another database)

Eighteenth Century Collections Online (searchable database of 18th century texts)

Feminist Philosophers

(more to come)