You mean focal statisitcs? I'm assuming you mean using this to fill in the gaps? I have tried this, and for when the gaps are really small, it works well. However, I'm finding that some of the gaps are quite large, so it would be preferable to find a workaround in that the "NoData" is merely ignored in the raster calculation (but still utuilizes the rasters where data is available). I'm rather surprised this isn't an option, actually. Am I missing something??
I should mention I still have 9.3, if this makes a difference.