At TopRank we’ve been building Google & Yahoo site maps ever since each search engine debuted the service. However, recently I’ve been focusing on how to better automate the process and optimize my time spent creating site maps. I’ve researched and tried tool after tool until I came up with one that worked well for us.
It all started at Google. Google actually lists out a bunch of third party resources. How convenient! You can see them here: http://code.google.com/sm_thirdparty.html
Ones listed under Programs/Code Snippets appear to be code that you add to your website to create your own sitemaps. What I was looking for is a program to create site maps for client sites, so those were out.