The last time (which happened to be the first) I downloaded pics from my daughters phone, it were ordinary jpg's. They should open in IE, (unless you've got another application installed to open jpg's with, like MS PhotoEditor or Irvanview), so that shouldn't be a problem. Maybe your sons cell phone sends the pictures in another format?
Things to do:
1. Ask your son what program he uses. Maybe it's one you have also. Then it comes down to configuring it.
2. See what type of pictures these are. That's the file type or file extension. Go into My Computer, then View>Folderoptions>View (this is Windows 98, it might be slightly different for XP) and uncheck the option to 'Hide file extensions for known filetypes'. Then save such a picture from the mail (it's attachment, I assume) to any folder you like, and use My Computer again to see the filename. It should be something like dsc78171.jpg, and then jpg is the filetype (the part behind the last dot). Personally I prefer the detail view to see that.
The program to use depends on the filetype, so the best thing to get an answer here, if your son can't help you out, is to post that.
my son sends me pics from his cell phone but I cant open them .... What application do I need to use? is there a download for this?
Thanks for your help