Is there a guide available for determining pedal/cleat combinations?
Those look like Shimano mountain SPD PD-M545 pedals:



Looks like a pretty good match to the picture on the Shimano site, but if you don't see a Shimano logo on them, they could be third party compatible pedals.

The cleats look like this:



I'm not aware of a guide that compares all pedal styles, but there are not that many pedal types in common use and most styles are different enough from each other that you can easily tell the difference between them.