This is how to remotely control/view your device from a PC and/or an Android Device.
The other operating systems in the title are just other ones that a possible, but since I don't own any of them, I will not be showing them.
Step 1: Supplies
You will need a Raspberry Pi, a Windows PC. Optional: Android Device.
Preferably a Raspberry Pi B+, a PC running Windows 8.Crap and optionally an Android Device running on 4.0.4 as that's what I'm using.
Step 2: Start Your Pi and Login to the GUI (get Past Inputting: Startx)
I'm sure you know how to do this.
Step 3: Open Up Your Terminal
Type in: 'curl -L -o VNC.tar.gz https://www.realvnc.com/download/binary/latest/debian/arm/
tar xvf VNC.tar.gz' without the two apostrophes ( ' ).
Step 4: More Typing
You'll have to go here because I can't paste Unix based sudo commands in this:
Once that's done, type: sudo reboot
Step 5: On Your PC
On your PC, goto: realvnc.com/download and download the latest .exe Windows VNC version.
Step 6: Get Your Licence
On the page that you ended up from downloading, press the licence button and once done choose a plan (might as well get the enterprise trail as it is free) then follow the steps until you have the licence code in front of you.
Step 7: Licence Your Pi
Only the server needs to be authorized so on your Pi's terminal type in: sudo vnclicense -add <licence>
Replace '<licence>' with your licence key.
Step 8: Find Out You Pi's Ip
Do this by going to menu-internet-VNC server, start that, and you should be able to see it there. Keep this open for now.
Step 9: Connecting for the First Time!
Start up VNC viewer on your PC, type in your Pi's ip and hit connect!
Step 10: Password?
If it asks for a password (which unless you've changed your Pi's settings, it should) type in your Pi's password (the default is: User: pi Pass: raspberry).
Step 11: Optional Android
Go to the play store and look for: Real VNC. Download that, then basically do the same things as I showed for PC.
Step 12: End
If there's is any step that doesn't work, don't hesitate to ask me, I will try my best to solve your problem. I will be adding how to control a computer from your Pi in the near future.