Google Cardboard
Your phone will need to have a Gyro and be Android 4.1 or above or iOS 8.0 or above.

One quick way to check if your phone is good for Google Cardboard VR is to try the #360 videos on Youtube

1. Goto Youtube 

2. Search for #360 

3. Play a movie  on the list
 I like  the "Mega Coaster"

If the image moves when you move your phone then you have a gyro

Good for Cardboard? 
If you see the Cardboard icon in the bottom right and when you click it your screen divides into two then you are good for Cardboard

See the video below for a quick demonstration

No Gyro!

There are a small number of VR apps that still work without a Gyro ... we'll be making a list below

Dive City Rollercoaster (Android) .. this works even if your phone doesn't have a Gyro
Check out the VR aps from Fibrum on Android & Ios - many of these work without a Gyro