I Wanna Make A Site

if its copyrighted material, then yes

well ill be careful lol. look for the site soon :)

1. Most likely, yes it would be illegal. There's not a lot of copyright-free content that people actually want. You're not allowed to redistribute music videos, movie trailers, or TV shows without permission from the studios/networks.
2. For a video site, you would need massive amounts of bandwidth and storage space, and the hosting won't come cheap.
3. You need the knowledge to actually code or implement a CMS for handling multimedia such as videos. Actually getting the site on its feet, or at least what I would consider a decent quality site, would take an enormous amount of work for what would probably be a short-lived operation (because of the lack of popular non-copyrighted content).

There are a ton of other issues, but those are the ones that spring to mind. There are simple tools out there for people to convert the video they already own; it's probably best if everyone does it themselves. That's my opinion.

That's really great that you're willing to convert video for people--which will take a lot of time--but that still doesn't get around the fact that you can't just hand out videos that you don't have permission to distribute. TV shows, movies, music videos, movie trailers, you can't just pass it out to people because they request it. You'll eventually get slammed. You could wind up with a huge fine or maybe even jail time. Heck, the TV bittorrent sites got shut down earlier this year, and they weren't even hosting the videos, just trackers TO the videos. If you start giving them out, I'd be afraid you're not going to know what hit you.

And you don't need QuickTime Pro. All you need is Videora. There's tons of other free tools out there that will do the job too, but Videora's practically pre-configured and dummy-proof. It reportedly does work, you just have to pick the right settings.

there are ways of doing this, main question would always be: is it commercial or not?

and free, "people made" content will be very big... still new and in "alpha", but this is very interesting: ourmedia.org