John:

Yes, you will want to resubmit any time you make changes to your website. I have taken the liberty of copying the text from the Google Website below.

Sitemaps are particularly helpful if:

• Your site has dynamic content.
• Your site has pages that aren't easily discovered by Googlebot during the crawl process - for example, pages featuring rich AJAX or Flash.
• Your site is new and has few links to it. (Googlebot crawls the web by following links from one page to another, so if your site isn't well linked, it may be hard for us to discover it.)
• Your site has a large archive of content pages that are not well linked to each other, or are not linked at all.

Hope this helps!

http://www.koolspaces.com
The Best Funny Videos on myspace