Make sure you have them in iTunes then select the sync movies option when you have your iPhone plugged in and the movie will be viewable in the videos app.
No
if you want to record videos, then you can find tons of apps that will allow you to shoot videos.
Sort of. You can download videos through Podcast.
Jailbreak any iPhone 3G (may work on previous generations, I'm not sure) and use Cydia to download CyCorder. This allows you to record video with your iPhone's camera into .mov format. As far as I am aware (correct me if I'm wrong), you need to SSH into your Jailbroken iPhone to get the videos out (root/var/mobile/Media/Videos), so you may want to get OpenSSH and the iPhone tunnel suite as well.
A program you download over the enternet and you use it to put songs, or videos on your ipod, iphone, mp3 player, ect.. itunes is a program that lets u buy music, videos, and games for your ipod.
If you are using Cloudsync get the desktop manager for it. It has an upload folder that will put supported videos and photos back into you Photos app.
You can sync your iPhone to iTunes to transport music, pictures, videos, etc.
When you sync your iPhone with iTunes or Finder, videos can be transferred to your device from your computer, or vice versa, depending on your settings. If you sync videos from your computer, they are stored in the "Videos" app or the "TV" app on iOS devices. Conversely, if you are syncing videos from your iPhone to your computer, they will be saved in the designated location on your computer, typically within the iTunes Media folder or a specific directory you choose.
I would say that a sanyo camcorder is beter than recording videos with the iphone because camcorders have more capabilites than an iphone recording videos.
Yes, you can put an iPhone camera in an iPhone 3GS provided you have the required skills.
To download videos on Move Star Planet, you can download the application for your iPhone. Then, create a movie on the website and add that movie to your iPhone account.