I'm on Verizon and I finally got the latest update on my GS3 that allows me to do some of the same cool stuff that can be done on the GS4. One of the things I have been excited to use is the multi-window mode. There is a really good tutorial by Josh Smith over on GottaBeMobile.com. Click here to go check it out!
One recommendation: when you get over there, click on your Evernote Clearly button. :)