Howell'ing at Statistics A site which supports David C. Howell's book, Statistical Methods for Psychology, but includes lecture notes and refresher tip sheets useful to all
Lecture Notes on Statistics and Data Analysis Prof. Forrest W. Young provides a site in support of Gravetter & Wallnau's Statistics for the Behavioral Sciences (5th Ed.) (2000) but the lecture notes are so extensive they constitute a mini-book in themselves
Psychological Statistics by M. Plonsky, PhD, University of Wisconsin at Stevens Point. Again, lecture notes so extensive they are like a textbook
Psychstat.MissouriState.Edu "Links to three different editions of my on-line introductory statistics text" plus helpful javascript applets, from David W. Stockberger
Research Randomizer "a free web-based program that permits instant random sampling and random assignment"