Comment on WordPress SEO Tutorial by SEO Dave.
Stallion has no way to alter the Google sitelinks, see http://googlewebmastercentral.blogspot.co.uk/2011/08/introducing-new-and-improved-sitelinks.html
Stallion can have an impact on the Google Meta Description, on each edit Post page there’s a box to add a Meta Description Tag, if you add some text there it might be used by Google as that posts meta description (note MIGHT, Google doesn’t have to use it).
To set a home page meta description tag go to the Stallion All In One SEO Options page and there’s a box for adding a description there.
If the Stallion All In One SEO Options page isn’t active turn it on at the top of the Stallion SEO Advanced Options page. For the meta descriptions to show you have to have “Stallion All in One SEO ON” set on the Stallion SEO Advanced options page.