We have created a general methodology for calculating the wavelength-dependent light curves of close-in extrasolar giant planets (EGPs) as they traverse their orbits. Focusing on the transiting EGPs HD 189733b, TrES-1, and HD 209458b, we calculate planet/star flux ratios during secondary eclipse and compare them with the Spitzer data points obtained so far in the mid-infrared. We introduce a simple parameterization for the redistribution of heat to the planet's night side, derive constraints on this parameter (P_n), and provide a general set of predictions for planet/star contrast ratios as a function of wavelength, model, and phase. Moreover, we calculate average dayside and nightside atmospheric temperature/pressure profiles for each transiting planet/P_n pair with which existing and anticipated Spitzer data can be used to probe the atmospheric thermal structure of severely irradiated EGPs. We find that the baseline models do a good job of fitting the current secondary eclipse data set, but that the Spitzer error bars are not yet small enough to discriminate cleanly among all the various possibilities.