Google just release its new beta Google Sitemap Generator program.
Sitemaps are an easy way for webmasters to inform search engines about pages on their sites that are available for crawling. By creating and submitting Sitemaps to search engines, you are more likely to get better freshness and coverage in search engines.
This program works on Windows IIS, Linux i386, and Linux 64bit. Licensed under Apache License 2.0.
I have not tried this program. It said it can make XML Sitemaps for Web Search, Mobile Sitemaps for mobile-friendly websites, and Code Search Sitemaps for source code.