Cisco released IOS-XR on VM called XRv. You guys can use it to study for your CCNA, CCNP, CCIE for SP track. 

Download it, Install it and go for it.

XRv download link:

http://software.cisco.com/download/release.html?i=!y&mdfid=285013070&softwareid=280805694&release=5.1.1&os

Installation guide for the VM for ESXi:

https://supportforums.cisco.com/docs/DOC-39939

A brief tutorial:

https://supportforums.cisco.com/docs/DOC-39962

Have fun.