kevyt,

Assuming you already have the URL that you want, its a simple regex. This regex makes a few assumptions, primarily that the URL will always look like this.

print "UID: $1\n"
  if ($url =~ /^http:.*\/ID=(.*)&MyToken=.*$/);
[download]

You could also push them onto an array and store all the values that you come accross:

push (@uid_list, $1)
  if ($url =~ /^http:.*\/ID=(.*)&MyToken=.*$/);
[download]