[BioC] cross validation / bootstrap after classification

[Heike Pospisil]

Hello Bioconducters,

I used t-test and/or SAM to find significant genes describing the differences in 
hgu133plus2-chips of two different phenotypical classes. The resulting heatmaps 
show a promising clustering.

Now, I would like to confirm these clusters and to estimate the robustness of 
this clustering by cross-validation and/or bootstrapping(*). For that, I have 
two questions:

1) Does there exists an appropriate package and/or source to perfom 
cross-validation and/or bootstrapping?

2) Which is the right measure to rate the goodness of such a clustering? By now, 
I looked over the cluster plots(**) and decided if it was good or a bad clustering.

Thanks in advance for any suggestion.
Best wishes,
Heike

*  with varying chip - subsets
** heatmap(exprs(sub),Colv=as.dendrogram(hclust(dist(t(exprs(sub)), 
method="euclidean"),method="complete")))