VM2 Social Share supports Joomla! 2.5, Virtuemart 2.0 and common social networks (Facebook, Twitter, Linkedin, Google, Pinterest, etc.).
+ Supports Joomla! 2.5 native & Virtuemart 2.0
+ Supports browsers: IE7+, FireFox, Chrome, Safari, Opera
+ Supports Facebook Like, Facebook Send, Tweet, ReTweet, Google+, Linkedin, Stumbleupon, Digg, Pin it and Bookmark & Share and will supports more common social networks
+ Meet Joomla! 2.5 requirements
+ PHP safemode off
+ Virtuemart configuration option “Enable Joomla Plugin” is checked.
If you are not using the default Virtuemart 2.0 template (use a third-party Virtuemart template), the extension will supports 3 positions: "After the title", "Before the description" and "After the description" and you need make sure the template supports plugin events: afterDisplayTitle, beforeDisplayContent and afterDisplayContent.
See this post to know how to check whether your VM template supports above events or not and how to fix it.