Fortran 90 and IDL procedures have been written to read the WMAP I,Q,U,S skymap
files.  The Fortran software requires the CFITSIO library; this can be
downloaded from http://heasarc.gsfc.nasa.gov/docs/software/fitsio/fitsio.html
The IDL software requires the IDL Astronomy Users Library; this can be
downloaded from http://idlastro.gsfc.nasa.gov/

The Fortran software consists of three subroutines:
WMAP_Read_Map   - Reads the I,Q,U,S maps and the covariance matrices from
                  a WMAP combined temperature/polarization FITS file.  It
		  is stored in wmap_read_map.f90
WMAP_Read_NInv  - Reads a WMAP Res 4 N-Inverse FITS file.  It is stored in
                  wmap_read_ninv.f90

WMAP_Read_Ninv_Weighted_Map - Combines WMAP_Read_Map and WMAP_Read_NInv.  These
                  two files are read and the N-Inverse matrix is multiplied
		  into the maps.  Only the maps are returned.


Separate 'header' files containing interface blocks for these two subroutines
are available (wmap_read_map.fh and wmap_read_ninv.fh) and should be used; both
subroutines use optional arguments.  When linking these subroutines into a
program, it is necessary to include the CFITSIO library in the link command. 
For example,
f90 -o test test.f90 wmap_read_map.f90 -L/usr/local/lib -lcfitsio
The same optimization arguments used to build CFITSIO should be used when
building this software.

The IDL software also consists of three procedures, with the same names as the
Fortran subroutines.  The argument lists are different, however.  The IDL
Astronomy Library should be in the IDL search path.

Please examine the prologs at the head of each file for more usage information.