Vbulletin is in the folder "/forum", and Wordpress "/blog"

What is the best solution for the sitemap?

There are plugins for both that can take care of making a site map for them. You then can submit them separately or use a master sitemap to submit them together.

There are plugins for both that can take care of making a site map for them. You then can submit them separately or use a master sitemap to submit them together.

Thanks for your reply.
What is the best? xx sitemaps or a master sitemap?
How to make a Master sitemap?

Go to sitemaps.org and follow their instructions for a master sitemap. I don't believe it is difficult at all.

There is no real difference between the two as far as I know. I guess a master sitemap might be better as it keeps everything clearly under one sitemap.

commented: Fast and pertinent answer. +1

Thank you Stymiee!
The answer is on sitemaps.org
Using Sitemap index files (to group multiple sitemap files)

<?xml version="1.0" encoding="UTF-8"?>
<[U]sitemapindex[/U] xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">
   <[U]sitemap[/U]>
      <[U]loc[/U]>http://www.example.com/sitemap1.xml.gz</loc>
      <[U]lastmod[/U]>2004-10-01T18:23:17+00:00</lastmod>
   </sitemap>
   <[U]sitemap[/U]>
      <[U]loc[/U]>http://www.example.com/sitemap2.xml.gz</loc>
      <[U]lastmod[/U]>2005-01-01</lastmod>
   </sitemap>
</sitemapindex>