Google SiteMaps XML file

Script to update .xml automatically with new web pages?

[1Lit]

Is there a script to update the sitemap.xml file automatically and then call Google to pick upt he ammended .xml file?

There are a lot of free sitemap generators out there, but it would be a real hassle to manually update the .xml every time we added new pages.

My second question is, is it necessary to use Google's sitemap generator [google.com] which is quite complicated (is it complicated because it does the automated update I'm asking about above?)?

Which are the simplest and best generators to use?

Thank you.