So its been almost a year since i've last been here

I'm curious to know is there a page i can go to see all the changes that are in 4.6

the last unity engine i had was 3.0/3.6 I also had licenses for that would they carry over?

also has much changed when it comes to the programming side of development?

 

So... You have retuned, just as the prophecy foretold.

Here are the changes for 4.6: http://unity3d.com/unity/whats-new/unity-4.6

As for the programming side, not much has changed.
Whatever you were doing in 3.6 should still work.

 

Some important changes to Transforms and GameObject's SetActive have happened, so you should check those out. The old animation system is now deprecated and is being replaced with Mecanim, so you should check that out. In 4.6 the first cut of the long awaited new GUI system was shipped, so definitely check that out for any new projects you start. The Editor also now has a dedicated 2D mode, and there's specialized sprite functionality and dedicated a 2D physics engine included to suit as well.

Aside from that stuff there's also a slew of minor additions, which you can find on the various Whats New pages as per Sir.Tiddlesworth's link.