Attachments within Calendar meetings are taking up a great deal of space on the users mailbox and Exchange mailbox server.  What is the best way to clean up old meetings with attachments that users no longer need?

Is there a command to run to view Calendar size for all users?  Exchange 2010

try this 

http://www.codetwo.com/admins-blog/how-to-remove-attachments-from-exchange-mailbox-database-to-reduce-its-size/

So your options would be to

1. Remove them via the multiple options offered within the article Vishwanath provided
2. You could use the archiving within Exchange to preserve them within an archive
3. Use a 3rd party product like Lucid8's DigiScope http://www.lucid8.com/product/digiscope.asp to find and delete/purge items that meet your criteria
4. If you want to get your hands dirty with VB, this might work http://www.slipstick.com/developer/remove-attachments-from-sent-messages/
5. Or this http://www.experts-exchange.com/articles/3562/Export-or-Strip-Email-Attachments-in-Outlook.html