Question about sitemaps and robots.txt??

Hi guys,

I have just finished off my site and changed the wordpress privacy settings so that google can now see the site. I then installed the popular google xml sitemap plugin and this created two sitemaps: mysite.com/sitemap.xml and mysite.com/sitemap.xml.gz

I then went over to webmaster tools and successfully added both sitemaps. I now want to create my own robots.txt file as i have a few things i wish to hide from google.

Do i add both sitemaps to the robots.txt file or just one? If so which one? The .xml or the .xml.gz?

Thanks for your help.