Usually the upconversions are done through menus on the DVD players and I believe most TV's will upconvert depending on the setting you choose when setting it up as well. I find if I go into Best Buy or Future Shop I can usually get the salesperson to let me have the remote and from there I can check the TV settings and every so often I am able to get a hold of the DVD or source remote as well, then I can check its settings also.
1080i and 720P are waaaaayyy better than 480P. Think about it, almost twice as much information in a 720P signal as a 480P(240 extra lines actually)) and 1080i(540 drawn twice to get the interlacing)has an additional 60 lines of resolution times 2 for an extra 120 lines. On a big screen it is very noticable, especially a few feet away. The farther back you go the less you can pick out, which is why the bigger you go, the higher the resolution you need, as the eye starts picking out the pixels because the pixel size would need to grow to accomodate the larger screen, if it were to stay at the same resolution as the smaller screen.
