To make my sitemaps for websites I've been using the top ranking program http://www.xml-sitemaps.com/ - however when trying to sitemap a website that is built with Joomla and uses Virtuemart then it seems to hang before completing.
You need to add the component and plugin and once set up then usage is pretty simple
>> go to component on the component list in Admin
>> click on the the '+' next to add menu and add the menu's you want the script to search through
>> to find your sitemap.xml goto the 'options' dropdown on the right and click on preferences.
>> now under 'Sitemap's URL' you can right click and open the link in XML Sitemap input box.
>> from here I've been going to source and copy and pasting to my sitemap.xml and then alerting google, Yahoo, Bing. However i'm sure there's a better way to do this. If you know it then could you let me know. Thanks