MorePower 6.0 (see Campbell & Thompson, BRM, 2012) is a handy statistical calculator for MS Windows that computes sample size, effect size and power statistics for ANOVA. It also calculates confidence intervals for ANOVA effects (Jarmasz & Hollands, 2009; Masson & Loftus 2003), as well as Bayesian posterior probabilities for the null and alternative hypotheses using a BIC approximation (Masson, 2011; Wagenmakers, 2007).

MorePower 6.0 is freely available here.