If i connect my laptop to my hdtv via vga cable, is that video quaility for vga considered 480i? My TV supports up to 1080i.
VGA only goes up to 480 (plus it doesn't carry audio in case you didn't know). If your laptop has a DVI output, that will carry HD (although again no audio and many TVs don't have DVI inputs).
VGA supports higher resolutions then 1920x1080. How do you think you have always been looking at your monitor that has always been 1024x768 or better? The VGA cable doesn't determine what resolution you get. That all depends on your source. So if you have a movie that is 480p, it will be 480p with a VGA cable. If you want to route the sound from your laptop to your tv, use a set of 3.5mm to RCA connectors.
The above is true, and your TV may well be 1080 capable but I doubt it would cope with that over VGA. My Toshiba is 1080i capable but its VGA displayable resolutions are as follows (as per VESA standards): 640 x 480 (VGA) 800 x 600 (SVGA) 1024 x 768 (XGA) 1280 x 1024 (SXGA) To display 1920 x 1080 i have to use the HDMI input which is converted to DVI from my PC for Bluray playback.
