Totally separate entities.

Slingbox works with your tv/dvr set-top box. You can watch your slingbox from anywhere since it is a one-to-one connection (your computer to your slingbox).

You can view Netflix movies and stuff Instantly after you log-in to the Netflix portal. Since it is an internet service, they restrict you to viewing only within the US. Applies to computer or iPhone app. You can get around the US only restriction if you have a VPN service that makes it look like you are in the states. VPN is also handy in DXB.

VPN service is becoming another must-have for international folks because it protects you and your data from prying eyes and ears, as well as letting you appear to be in the states for copyrighted/restricted services like Netflix. I'm a happy customer of WiTopia, it's the best pay-for-it deal I've found on the net that has no bandwidth restrictions.