Conference Calling App for the UK

[oper8or]

Looking for the best Conference Calling App for use in the UK. Very close friend of mine from the UK just got the S3 and makes several conference calls a day. His corporate IT forces a security system on his phone that make conference calls too tedious to be practical. He read up on the MobileDay app and liked everything about it except for the fact that it is not available in his playstore. Anyone know of one that is as good in the UK playstore?