With Facebook we have the Open Graph tags that allow webmasters to specify how the story is displayed on Facebook.
Is there something similar for the Google +1 button, that allows webmasters to specify the thumbnail image, description and title? Google+ seems to be ignoring the og-meta tags.

From Google+ help docs, we now have an official answer.
Google uses schema.org microdata to generate rich snippets in search (and in Google+). There’s a lot written about schema.org and how it relates to Facebook OpenGraph in these two links:
See: http://www.google.com/support/webmasters/bin/answer.py?answer=1211158
See: https://developers.google.com/+/plugins/+1button/
Some important bits: