Yes....have been using this set up or www.telediscount.co.uk (worth comparing the locations you want to call) for international calls for long time. Works well and charges what they say they do.
no need to register....just dial relevant access number , wait for message then dial full international number. just appears on your usual phone bill. usually a good quality line - better than the rip off companies like alpha telecom that make you pay in advance.
highly recommended ...infact spoke to my sister in Oz this morning for less than calling next door! www.telestunt.co.uk