Later versions of IRAF (v2.10?) became able to handle FITS image files. FITS is a widely accepted standard and is far more portable than the native IRAF format was (if I recall correctly, before IRAF V2.11 the .pix files were even raw binaries that got mangled when moving from big-endian to little-endian machines). This was a major step forward. And if you want to write programs to access FITS files, you can use the FITSIO library.
I wrote this a while ago, and there may not be anyone else left with a bunch of IMFORT-using legacy code. I'm putting this up in the hope it saves somebody else a headache. If you're dedicated enough to read this far, you may be one of those people. It does not implement all IMFORT subroutines, but most of the ones that you need to access 1-d and 2-d images and image headers. The code is simply two Fortran files:
fitsiowrap.f - all the subroutines
nmax.f - header file that defines the biggest image you'll use
e.g. 2048, 4096, etc. edit to change.
FITSIOWRAP is free, copyrighted, and GPL licensed: fitsiowrap.tar
(I can't imagine anyone could actually sell this code, but what the heck, I always wanted to give some software away)
FITSIOWRAP doesn't include every last IMFORT subroutine. It has the common ones that I've needed. If there is a subroutine that you desperately need and it's not included, contact me and I might be able to implement it.
You can download the IMFORT manual provided by IRAF. It doesn't have the reference manual pages for commands (possibly the most essential part), though.
Contact: Benjamin Weiner, email bjw at earth.astro.umd.edu