@NNN2004
If your TV has a vertical resolution of 1080 and you feed it a 720p signal it will _necessarily_ upscale it to fill the screen.
Thus whatever the source of the 720p signal - a PS3, a cable box, a dvd/bluray player -, if you see a full screen image on a 1080p TV, then it means it is being upscaled. So you're done.
Basically on the PS3 the TV modes are autodetected, and you can't generally force all games to upscale. On the 360 you can force to upscale, and you can test outputting 720p or 1080p to see which image quality is better with your setup.
A little con of the 360 method: if you set it to upscale to 1080p and then connect it to a 720p TV, you will basically upscale 720p->1080p with the 360 chip then downscale 1080p->720p with the TV chip. The result of the double scaling will probably be a slight degradation of the image.
Again same disclaimer: if someone knows differently on the subject, please jump in and correct me.
