asremlPlus augments the use of ASReml-R in fitting mixed models and packages generally in exploring prediction differences.
ASExtras4 contains utility functions for the meta-analysis of a series of spatially defined field experiments.
This 2007 presentation was given by D.G. Butler, B.R. Cullis, A.R. Gilmour and titled ASReml-R: an R package for mixed models using residual maximum likelihood.