Where can I find a sitemap generator?

Google has a sitemapping service here, I used it once in the past; I don't recall whether or not it has all those services, but it's certainly worth a try (and free).

www.google.com/webmasters/sitemaps

Unfortunately, that Google service is for tracking visitor information, not for generating sitemaps. I had a look at it earlier. Thanks though :-)

look into link-checking tools (like Linkbot on Windows), they sometimes have sitemap as one of the report outputs.
Or... my guess is that there is PERL or Python script that would do it, check sourceforge.net

MarkHeftler was on the right track, but he provided the wrong link. You can use the Google Sitemap Generator, a Python script that, um, generates sitemaps.

Defining your sitemap in Google's XML format has a couple benefits:
1. Google has licensed their Sitemap Protocol under the terms of the Attribution-ShareAlike Creative Commons License, so other search engines can make use of it (and you, theoretically, only need to create one sitemap, which all search engines can use to index your site).
2. The protocol allows you to specify meta data that Google uses to optimize its crawling and indexing of your site (like when your pages were last modified and which pages have the highest priority). If Google is the most important search engine for driving traffic to your site, it’s probably smart to define your sitemap in their preferred format.

If you need to create XML, HTML sitemap files for your sites or to notify search engines about updated sitemap files use http://www.sitemapwriter.com Sitemap Writer Pro. I tried different software for creating the sitemap for my website. This is the most effective one among 5–6 programs I tried.
This powerful webtool generates the sitemap for your website in just seconds. Mayor search engines (Google, Yahoo, Ask, MSN, Moreover) are able to index and read your sitemaps without any problems.