Can anyone tell me how to revert (roll back) a checkin in TFS 2010?
You have two options for rolling back (reverting) a changeset in Team Foundation Server 2010 Version Control. First option is using the User Interface (if you have the latest version of the TFS 2010 Power Tools installed).
The other option is using the TFS 2010 version control command-line application:
tf.exe rollback
I have information about both approaches on my blog post.
For Team Foundation Server 2012, 2013, or Visual Studio Online, rollback is now built-in directly to Source Control Explorer and when you are opening a changeset's details in the Team Explorer Window. You do not need to install any release of the Power Tools for this functionality when using Visual Studio 2012 or later. There is a great MSDN article discussing details about rolling back a changeset now available here: http://msdn.microsoft.com/en-us/library/ms194956(v=vs.110).aspx