You might have a look at this company;
http://www.0044.co.uk/global-sim-card.htm# The international sim card gives you a Uk number (Isle of Man I think), so that people calling you only have to make a local UK call. And of course there are no charges to receive calls in most, if not all, of Europe as far as I remember. I spent ages looking into this and they seemed the best as some of the 'free to receive calls' sim cards give you a number from some very strange countries indeed which are quite expensive to call from the UK.
Hope this is of some use.