rotating raster maps

[BARNES DAVID]

If anyone could help... I have many air photos that were scanned in as tif 
files that were imported into GRASS as raster files. The problem is that 
the north end of the photos were not orientated to the top of the map or 
in this case, the top of the screen. The plan is to geo-reference these 
images to UTM coords and to rectify the images. I have not been able to 
find a program within GRASS that would allow me to rotate these images. 
Does such a program exist? Or do the photos need to be scanned in with 
north orientated to the top of the screen?

Any comments would be appreciated. Thanks. 

  **********************************************************
  * My Address                                             *
  *                                                        *
  * DAVE BARNES                                            *
  * Geology Dept.                                          *
  * Western Michigan University                            *
  * Kalamazoo, MI 49008                                    *
  *                                                        *
  * email address                                          *
  *                                                        *
  * barnesd at lab.cc.wmich.edu                               *
  **********************************************************