NetCDF-4.0 is currently available in alpha release. It allows the use of HDF5 files from the netCDF API. New features available with netCDF-4/HDF5 files include:
NetCDF-4 also contains a complete upgrade of the installation and build system, including the use of the libtool package to build shared libraries on systems which support them.
More information about netCDF-4 can be found at the netCDF-4 web page http://www.unidata.ucar.edu/software/netcdf/netcdf-4.
For more information about HDF5, see the HDF5 web site: http://hdf.ncsa.uiuc.edu/HDF5.