Change SharePoint 2010 User Interface to MOSS 2007 Look and Feel

Yes, Its possible to provide MOSS 2007 User interface to the SharePoint 2010. There are two ways:

1. If you have upgraded from MOSS 2007 to SharePoint 2010 using In-Place upgrade, then you will be able to do it by GUI. Here is where: Site Actions >> Site Settings >> site collection administration >> Visual Upgrade
2. You can do the same with PowerShell. Of course if you have new installation or DB attach method used, you can do this ONLY with PowerShell.

   $web = Get-SPWeb <sharepoint-url>
   $web.UIVersion = 3  //set it to 4 if you want SharePoint 2010 look and feel
   $web.Update()

So here is the result, With UIVersion 3:

With UIVersion 4: