Was there are reason you overlooked all the 3rd party titles that are more popular on the PS3? FIFA 10 has sold 2.85 million on the PS3, 2.24 million on the 360. PES 2010 has sold 1.92 on the PS3, 0.62 million on the 360.
Then there are former PS2 exclusives that have had sequels made for both consoles. Tekken 6 has sold 1.32 million on the PS3, 0.66 on the 360.
From this (very narrow) comparison you could say the PS3 is dominating the 360 in software sales.