I assume you can use 6 cameras facing all directions to get the full 360 image, but how could you get the actual 360 kind of image like the in videos that are since recently on youtube?
If you have 6 cameras you can get the complete view of the scene, but how do you render that into a single image?
You might be able to accomplish this with one camera by mucking about with the cameras projectionMatrix
Using multiple cameras, you can just render them to the screen wherever you want them like if you were doing a 2 player split screen game. If the cameras views were aligned properly then it should create the effect you want, though I’m not sure it would look correct at the seams. You would just have to try it for yourself and see if it looks ok or not.
Look into panorama cameras. There are several assets on the asset store that might do what you need.
Simple thing would be to render to a cubemap, and then take the cubemap and render it into an equirectangular texture. Alternatively, you can render the 6 scene views and do the same thing. As mentioned, the resources on the asset store should help guide you!