If you someone sends you a Microsoft Visio file and you need to view the contents, then don’t go out and blow money just to open the file! Download the Microsoft Visio Viewer for FREE!
You can get the Microsoft Visio viewer here http://www.microsoft.com/downloads/details.aspx?FamilyID=d88e4542-b174-4198-ae31-6884e9edd524&displaylang=en
The drawback is that you cannot edit or create Visio documents using the Visio Viewer.