All you need is the Slingplayer client.
You can get the
- Slingplayer Desktop for PC (http://support.slingbox.com/go/windows-download-desktop-us)
- Slingplayer Desktop for MAC (http://support.slingbox.com/go/dl-mac-desktop)
- Web Slingplayer Plug-in (http://watch.slingbox.com/)
Note, these are US links, and may affect your differently due difference in regional services and availibility.
If you're not in the US, I suggest that you get the Slingplayer Destktop download by following the "Support" tab at the top of the screen, just below it there's the "Downloads" button. You'll have to go through each page looking for the appropriate Slingplayer Desktop link as each page is different. The web master that control Sling's web pages knows nothing about setting up a common user interface.