It really depends on your needs. You could try A1 Sitemap Generator if you have a large/complex website, care about xml sitemap priority calculation or need an advanced HTML sitemap.
http://www.wonderwebware.com/sitemap-generator/ i use this. i think it is good. you can creat xml sitemap for google,yahoo, html etc. try this one good for beginner like me
http://www.xml-sitemaps.com/ http://www.auditmypc.com/free-sitemap-generator.asp I use those fairly regularly without issue. If it works, it works hope that helps, Nigel
http://www.sitemapwriter.com - with free html sitemap creator tool and free sitemap submitter to major search engines