You will get 1200 minutes that can be used to call numbers starting with 01, 02, 03 and all UK mobile networks. Unlimited person to person texts to UK numbers and 1gb of data per month.
The unlimited calls and texts to Virgin mobile numbers is on top of the above allowances. The 60 minute thing is basically if you are talking to someone for 59 minutes the call is free, if you go over 60 minutes then you will get charged but i'm not sure if you get charged for the whole call or just what you used after the first 60 minutes.
All this info is available here
http://store.virginmedia.com/virgin-...nthly-sim.html in the 'General Mobile' section of the legal stuff.