Any large benefit from a wheel upgrade is almost entirely psychological. Weight differences are significant mainly when accelerating and climbing, and even then many people forget to include the rider when assessing the impact of weight savings. Saving a huge 1.5 lbs on a 20 lb bike (7.5%) sound great until you add a 180 lb rider, which changes it to .75%. Even that does NOT save you .75% of your energy, as wind resistance is a much higher factor. If your riding consists of a 1/2 hour climb followed by a bus ride back down the hill, or you live in a 4 story walkup then by all means buy lighter wheels before you do any other upgrade.

When I bought my bike I put my money into tires (stock ones were heavier duty than I needed) and then stem, handlebars, and saddle (because comfort and fit have a big effect on efficiency and endurance).

As for resources to learn more, just hang out here or simply use Google. Bicycle wheel recommendation seems to bring up a mix of specific recommendations and general information, or just do bicycle wheel.

I've said many times that much of the time spent on this forum obsessing about how to make one's bike faster/better would be more profitably spent on the bike.