If I want to download CUCM and install in a windows virtual
environment, which version do I download from software centre
You cannot apply for license key, you need to buy licenses ahead of time and then register them for license key.
Either way if this is just for playing and you have access to the CUCM download files, download latest 8.6 version and use Roman's or others' method to make the media bootable and you will get demo license with it that will allow you to install about 40 or so devices with no expiration date.
HTH, please rate all useful posts!
I think he's just talking about running CM in a VM in VMware Workstation on Windows. He probably just want to practice/demo it. It's not like he can put it in production without licenses.
Regarding turning non-bootable DVDs into bootable, I've done around 30 CM/CUC 7/8 installs using this method. There are plenty situations where you just don't have the DVD with the right version, and this method is just fine. Cisco TAC never tried to check for this with me, and I doubt there's a way or if they even care.
UCCX ISO is an exception, they don't include CAD/CSD upgrades on the non-bootable ISOs, so you want to make sure you have the real DVD for the new install.