Looking for a tool for Orthorectification of Archived Air Photos

You could try AirPhotoSE - it's free but not open source - which is part of BASP (The Bonn Archaeological Software Package). It's designed for Windows, but it should work well under Wine on Linux.

I believe the author, Irwin Scollar, is intending to make the full version of AirPhoto open source in the near future, but I've not got any dates for it yet.

You might like to have a look at the GeoRect tool that comes with FalconView