Customization

Hi
 
I want to customize my 
'Edit ring'  and 'Edit site' forms but I can't find which file it is 
to alter.  Firstly I would like to allow changes to the ring id and the 
site id on these forms.  There are other bits of customization I wish to do 
to these 2 forms so that they match the customization changes I have made to 
the 
'Add new ring' and 'Add new site' forms.  Can anyone help me on this one, 
please?
 
Thanks in 
advance.
~ Beauty 
~