I am using a sitemap creation script that adds a link to the top of the sitemap for the site of the script developer. Any views on whether that will in fact lose PR away from my own sitemap links? Or does a sitemap and it's links actually count as backlinks or rather are they simply used for google to initially index links, whilst the actual ranking is done from on-site backlinks etc? Any thoughts? thanks
Sitemap is for proper indexing and especially useful for larger sites, nothing to do with link juice.
Great, thanks. So the only benefit to the script developer is that if a human checks my xml site map they will find the link to his site.
Nope, you can have a html sitemap to do that. You should submit the xml sitemap to google webmaster tools but you don't need a physical link on your site for it.