It's appearing the revisions of operating systems to accommodate the new SoC on the Pi2. Let's see those already updated and those to come in the following article.
Raspbian y NOOBS: It was hoped that the official release is already adapted to change. What I liked most is the boot start with the 4 raspberries symbolizing the 4 cores of the new processor.
Debbian Jessie: One thing I need is to change from Wheezy to Jessie on Debian based distros to get the latest packages. Well, we already have a version to test with Kernel 3.18 + firmware occupying 3 GB.
OpenELEC: Our favorite distribution for leisure and entertainment has been updated updating to the kernel 3.18 and it works really well as you can see in the video that accompanies the article.
OSMC: Formerly known as Raspbmc is another distribution to run XBMC based on Raspbian but still is not very optimized in its Alpha 4 release.
Android?: See this post from linux.com.
Others: For other distributions that we use as Arch Linux, Pidora or Risc OS we also have to wait a few days or even weeks, but it will come.
Windows 10: It will take to arrive and not be a Windows to use as all imagine, but it sure we can use it for the IOT.
While I wait My Raspberry Pi 2 behind the door. Mr. Postman, if you're reading this, I promise you a beer if you are not late.