remove timestamp/watermark from digital images

[Alex Dean]

I just got back from a camping trip.  On said trip, I took hundreds of  
pictures I'm really happy with.  Except... the camera had some setting  
enabled which stamped the date & time in a really ugly red font in the  
corner of every image.  I'm hoping someone can suggest a process  
(ImageMagick?) to locate these stamps and remove them, maybe by  
copying adjacent areas of the image or something like that?

I know I could do them by hand in Photoshop or Gimp, but I'd prefer to  
start with some batch process and then fix up then ones where the  
batch output isn't acceptable.  The idea of doing them all by hand is  
a little overwhelming.

Any ideas?

thanks,
alex