Website for safari booking for national parks and tiger reserves in Rajasthan is http://fmdss.forest.rajasthan.gov.in/. Wasn't all that user friendly so here is how to do it. To create an account, click on SSO Login and then Register. I tried doing through FB, but eventually had to do it through Google. Once registered, login at the same place, then click on 'Rajasthan Wildlife' on the left hand side and 'WildLife ticket booking' thereafter. Earlier website is no longer used for bookings. Hope it helps.