[R] sample size computation for survival data

Does a package exist to help compute sample size for censored data? I am planning a study involving interval censored data. I know that there exists functions in stata for this, so I was wondering if R has similar facilities. So far I have not been able to find anything for R. Thanks for any

[R] N.cohen.kappa function for polytomous outcomes

Is there a function analogous to N.cohen.kappa (concord package) which computes sample size needed for a Kappa statistic with polytomous outcomes? I have just started using R and so far I am finding it is missing alot of things that Stata has. -