Miro runs on Windows XP, Vista and Windows 7.
Open up your favorite web-browser and go to http://getmiro.com/ .
Download the most current version of Miro.
Double-click on the Miro installer to install it.
Follow the installer directions.
Be sure to read the installer’s instructions, to understand the difference between the simple and advanced install options.
Miro runs on Mac OSX 10.5 and higher.
Miro 5.0 runs on Ubuntu Lucid, Maverick, and Natty.
Source code for Miro is available in versioned tarballs from http://getmiro.com/download/all/ .
Source code is maintained in a git repository. Details and web-interface are available at http://github.com/pculture/miro
Miro on Windows and Mac OSX will let you know when there is a new version of Miro available. Follow the directions that it gives you to update.
When new Miro packages are available, your Update Manager will let you know and walk you through updating.
Talk to whoever is packaging and supporting Miro on your platform for availability.