gimp-2.6.5-1.fc9.x86_64 appears to be missing a dependency on pygtk2, ditto current Rawhide's -4.fc11 based on looking at the specfile.

Without pygtk2 installed:

$ gimp
Traceback (most recent call last):
  File "/usr/lib64/gimp/2.0/plug-ins/python-console.py", line 20, in <module>
    from gimpfu import *                                                     
  File "/usr/lib64/gimp/2.0/python/gimpfu.py", line 75, in <module>          
    import gimp                                                              
ImportError: could not import pygtk                                          

(gimp:15840): LibGimpBase-WARNING **: gimp: gimp_wire_read(): error
Traceback (most recent call last):                                 
  File "/usr/lib64/gimp/2.0/plug-ins/colorxhtml.py", line 25, in <module>
    import gimp                                                          
ImportError: could not import pygtk                                      

(gimp:15840): LibGimpBase-WARNING **: gimp: gimp_wire_read(): error
Traceback (most recent call last):                                 
  File "/usr/lib64/gimp/2.0/plug-ins/py-slice.py", line 31, in <module>
    from gimpfu import *                                               
  File "/usr/lib64/gimp/2.0/python/gimpfu.py", line 75, in <module>    
    import gimp                                                        
ImportError: could not import pygtk                                    

(gimp:15840): LibGimpBase-WARNING **: gimp: gimp_wire_read(): error
Traceback (most recent call last):                                 
  File "/usr/lib64/gimp/2.0/plug-ins/foggify.py", line 20, in <module>
    from gimpfu import *                                              
  File "/usr/lib64/gimp/2.0/python/gimpfu.py", line 75, in <module>   
    import gimp                                                       
ImportError: could not import pygtk                                   

(gimp:15840): LibGimpBase-WARNING **: gimp: gimp_wire_read(): error
Traceback (most recent call last):                                 
  File "/usr/lib64/gimp/2.0/plug-ins/palette-sort.py", line 17, in <module>
    from gimpfu import *                                                   
  File "/usr/lib64/gimp/2.0/python/gimpfu.py", line 75, in <module>        
    import gimp                                                            
ImportError: could not import pygtk                                        

(gimp:15840): LibGimpBase-WARNING **: gimp: gimp_wire_read(): error
Traceback (most recent call last):                                 
  File "/usr/lib64/gimp/2.0/plug-ins/palette-offset.py", line 17, in <module>
    from gimpfu import *                                                     
  File "/usr/lib64/gimp/2.0/python/gimpfu.py", line 75, in <module>          
    import gimp                                                              
ImportError: could not import pygtk                                          

(gimp:15840): LibGimpBase-WARNING **: gimp: gimp_wire_read(): error
Traceback (most recent call last):                                 
  File "/usr/lib64/gimp/2.0/plug-ins/python-eval.py", line 20, in <module>
    from gimpfu import *                                                  
  File "/usr/lib64/gimp/2.0/python/gimpfu.py", line 75, in <module>       
    import gimp                                                           
ImportError: could not import pygtk                                       

(gimp:15840): LibGimpBase-WARNING **: gimp: gimp_wire_read(): error
Traceback (most recent call last):                                 
  File "/usr/lib64/gimp/2.0/plug-ins/palette-to-gradient.py", line 17, in <module>
    from gimpfu import *                                                          
  File "/usr/lib64/gimp/2.0/python/gimpfu.py", line 75, in <module>               
    import gimp                                                                   
ImportError: could not import pygtk                                               

(gimp:15840): LibGimpBase-WARNING **: gimp: gimp_wire_read(): error