Should be a fair few folk in the globe for this one mate.
Its on Niddry street which is between the Royal Mile (at the Bank hotel/Radisson SAS hotel) and the Cowgate.
http://maps.google.co.uk/maps?f=q&source=s_q&hl=en&geocode=&q=niddry+street+edinburgh&sll=53.800651,-4.064941&sspn=15.425044,46.582031&ie=UTF8&ll=55.949422,-3.186795&spn=0.000891,0.002843&t=h&z=19