Portal Building allows you to create ender portals where ever you want.
If you can't go everywhere like with nether portals, it's the speedest way to return to your bed.
To create a portal just build a 3x3 square of End Stone (to be sure you already reach the End) with an Obsidian at the middle, drop an EnderEye on the obsidian and it will turn into a portal.
To destroy the portal (cause it's normally unbreakable) place a glowstone block 2 blocks above the portal.
Please note that this will not work when you're fighting the enderdragon, you can't use this to run away.
Just run the command once in your spawn chunks, the system will build itself and will work everywhere you are.