What are some alternatives?
When comparing WonderWebWare Sitemap Generator and XmlSitemapGenerator.org, you can also consider the following products
DYNO Mapper - Create Sitemaps with the DYNO Mapper Visual Sitemap Generator.
GlooMaps - Create your visual sitemap on the go - easy peasy
MySitemapGenerator - Online XML Generator for SEO and eCommerce. Creates XML Sitemaps, Shopping Feeds, RSS.
A1 Sitemap Generator - A1 Sitemap Generator has been in active development and sold since 2005.
XML-Sitemaps.com - Free Online Google Sitemap Generator.
FreshRSS - FreshRSS is a free, self-hosted RSS aggregator.