sitemap

I Have a big B2B portal (almost 500000 Pages) and I want to create an XML Sitemap for this portal. Kindly suggest me best site or tools to create the sitemap for our B2B portal.

Hi, A site made this sitemap for me: <urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.sitemaps.org/schemas/sitemap/0.9 http://www.sitemaps.org/schemas/sitemap/0.9/sitemap.xsd">...

Hey there, What steps do I need to do to index my page and generate a site map for my new website? Kindly explain me through the procedure, please.