This is what the IPCC (the world's most authoritative body on climate change) had to say on solar forcing in its most recent report

"Continuous monitoring of total solar irradiance now covers the last 28 years. The data show a wellestablished 11-year cycle in irradiance that varies by 0.08% from solar cycle minima to maxima, with no signifi cant long-term trend. New data have more accurately quantifi ed changes in solar spectral fl uxes over a broad range of wavelengths in association with changing solar activity. Improved calibrations using highquality overlapping measurements have also contributed to a better understanding. Current understanding of solar physics and the known sources of irradiance variability suggest comparable irradiance levels during the past two solar cycles, including at solar minima. The primary known cause of contemporary irradiance variability is the presence on the Sun’s disk of sunspots (compact, dark features where radiation is locally depleted) and faculae (extended bright features where radiation is locally enhanced). {2.7}

The estimated direct radiative forcing due to changes in the solar output since 1750 is +0.12 [+0.06 to +0.3] W m–2, which is less than half of the estimate given in the TAR, with a low level of scientific understanding. The reduced radiative forcing estimate comes from a re-evaluation of the long-term change in solar irradiance since 1610 (the Maunder Minimum) based upon: a new reconstruction using a model of solar magnetic fl ux variations that does not invoke geomagnetic, cosmogenic or stellar proxies; improved understanding of recent solar variations and their relationship to physical processes; and re-evaluation of the variations of Sunlike stars. While this leads to an elevation in the level of scientific understanding from very low in the TAR to low in this assessment, uncertainties remain large because of the lack of direct observations and incomplete understanding of solar variability mechanisms over long time scales. "

This graph shows the relative importance of solar forcing when compared to other factors. As you can see, greenhouse gases have a forcing of around 2.5 Wm-2, against the solar forcing of 0.12 Wm-2.

For a debunking of the Mars stuff, see the always fantastic RealClimate at RealClimate » Global warming on Mars?