When I registered on incredicall, I was neither given a PIN, nor asked for one. So I can't help you sagarvijaykumar.
The number I got on Orange starts with 075890. As this is now charged on Orange - see
http://www1.orange.co.uk/service_plans/paymonthly/075890m.html - I don't care to find out if it works or not.
EDIT: Having just dialled the 0121 132 0050 number, I was welcomed to a "C-line conferencing service", which does demand a PIN.
My inference from this is that incredicall no longer have access to inclusive numbers for making calls, and have moved to a conferencing service instead.
So the query by sagarvijaykumar seems to be pointless now.