iRule regex to normalize phone numbers?

Or instead of string map, you can strip non-numeric characters:

%proc justNumbers {pn} {
  set nums "0 1 2 3 4 5 6 7 8 9"
  set newNumber ""
  foreach x [split $pn ""] {
    if { !([lsearch $nums $x] == -1) } {
      append newNumber $x
    }
  }
  return $newNumber
}
% set x1 "1-800-632-6223"
1-800-632-6223
% set x2 "1.800.632.6223"
1.800.632.6223
% set x3 "1(800)632-6223"
1(800)632-6223
% justNumbers $x1
18006326223
% justNumbers $x2
18006326223
% justNumbers $x3
18006326223

assuming of course you have 11.4 (procs support), you can use this function or a similar one with string map (might be a little faster) and call it as necessary from same or different iRules.