I did a quick google search to see if there was a quick run down on the steps you need to know about to do a WCS to NCS migration, and sure enough - the first google result was from my pal Samuel Clements. Sam outlines the features of NCS and the gotchas surrounding the NCS installer being a self-contained small, medium or large OVF file. Instead of installing NCS on a Windows or Redhat server, the VM is imported into an existing VM infrastructure.
If you choose the wrong selection from small, medium and large - there isn't a way to change it after the install without re-licensing the server and incurring an upgrade licensing fee in the process.
Sam has done a great job of listing the tasks that are necessary, so the only other thing I'll include here is a link to the Managing an Enterprise WLAN with Wireless Control System slide deck from CiscoLive 2011.
Key Enhancements with NCS:
15,000 Lightweight APs
5,000 Autonomous APs
WCS Supports up to:
3,000 Lightweight APs
1,250 Autonomous APs
Cisco has also started to create quick learning modules for NCS. They can be found here.
For the sake of brevity, (and being able to find them again) I created the bitly link bit.ly/NCSQLM to point to that URL. Previously, I did the same thing for the WCS quick learning modules: bit.ly/WCSQLM. That shortened link has come in handy several times when I'm not able to dig up the long url from an email I've sent.