Its really simple to add a sitemap to your Google Webmasters Website account. Below is a list of instructions on how to do it.....
1. After logging in and selecting the website account you would like to attach the site map too, in the left hand column click "Optimization"
2. Then click "Sitemaps"
3. Then in on the right hand side of the page click the red button called "Add/Test Sitemap"
4. In the pop-up window that appears in the text box just type sitemap.php
5. Click Submit Sitemap
6. Refresh your page and you'll see the new site map has been added to your Webmaster account.
And thats it! Nicely Done Pro!!!