Converting DEMs

[J. Brian Hughes]

I am trying to figure out how to use 1.0-degree Digital Elevation
Map (DEM) data to fill in the gaps in 7.5-minute DEM data.  This
involves converting coordinates from a latitude/longitude coordinate
system using the WGS 72 or WGS 84 datums to the UTM coordinate system
using the NAD 27 or NAD 83 datums.  Can GRASS help me to do this?
Has anyone out there done coordinate conversions involving these
coordinate systems?  I presume that if I can successfully get the data
into an acceptable form to be loaded into a GRASS database, then I can
save the information out to a file in a new coordinate system format.
Is this correct?  Any input will be greatly appreciated.

J. Brian Hughes