If you don't like the standard format used in Dynamic Numbers (xxx) xxx-xxxx you can change this with just a little bit of Javascript.
The first step is setting the _ibp_formatting variable to false in the Javascript that goes in the <head> of the page. This causes the number to be returned as an unformatted string of digits.
<script type="text/JavaScript">
var _ibp_public_key = "1234567890a";
var _ibp_formatting = false;
var _ibp_keyword_set = 1234;
</script>
Next insert the phone number as you normally would but put it inside an element that's hidden so it doesn't get displayed. When this script is included it sets a Javascript variable called _ibp_phone_number that is set to the unformatted phone number.
Actually it would rather be the following now: var new_number = _ibp_phone_number.substr(1,3) + "-" + _ibp_phone_number.substr(6,3) + "-" + _ibp_phone_number.substr(10);