I have a visitor in my home from another area who wants to pray and I wasn't sure which way he should face and there was noone around to ask.
Anyway, I found this handy on-line Mecca finder. It uses Google maps and you have to move the map so the place you are is under the red line.
I found my building on there and the direction for Mecca is shown by the red line. I had said to him the direction I thought (but told him I wasn't really sure) and turns out I was right.
Online Qiblah Finder