http://www.autositemap.com/ That's the best I've found, but it works in kinda a weird way. There is a .NET one floating around, but it stopped working after about 1300 pages crawled...
I just started using Google Sitemaps about 1 hour ago - already uploaded my first sitemap. I'm using GSiteCrawler from http://johannesmueller.com/gs/ real easy to use and it's Free
Try DMX ZONE's "Google Sitemap generator" at http://www.dmxzone.com/ShowDetail.asp?NewsId=10538 It is a Dreamweaver extension.
Agreed.I also use GSiteCrawler with no problems and I'm a total noob You can also pick out any urls you don't want to use before generating the map.
I just noticed today that Google actually has a list posted of third party sitemap generation tools... http://code.google.com/sm_thirdparty.html