Not sure what you are asking. Do you mean websites, or do you mean a physical location where you can practice a mock neonatal code?
When we have our NRP cert/recerts, we have staff who are certified NRP instructors run the mock codes on-site. If you are talking websites, I don't know if they exist or not. It seems that it would be very difficult to practice via website since a code is a hands-on experience.
Don't know of any websites, but do your own mock code with the scenarios in the book or with ones you can make up as you go along. We do these alot.
Also...make sure the person knows where the UAC kits are, the emergency drug box (if you have one) is, how to set up oxyhood quickly, etc...