It looks like many people are working on this issue, there are routines being developed right now, that will appear soon. There are also existing functions, as you see when you read on.
Conversion is certainly quite easy, but requires some effort.
I think that the best, if you are interested, would be to send you just the part concerned with the between-block covariance calculation, which you could easily include in your kriging program. Doug McIver suggested using a freeware package called geoeas which has block kriging. It was not finished yet when he wrote. R. Reich has developed several functions for doing kriging and cokriging that he uses in his class in spatial statistics.