Here’s how:
You need a movie file. The most common types are ISO, IMG, AVI (divx or xvid). I am not talking about renting movies from iTunes. The normal course of events to get a file like this is to download a torrent in rar format, extract the files, and it gives you something like an ISO, IMG, or AVI file.
The next thing we have to is convert these file types to MP4. To do that, the program I use is VisualHub. This is the best video converter I have found for Mac. It is $25 but is worth every penny. It’s also very useful if you have an AppleTV. I don’t use the free program Handbrake because I have trouble converting certain types of files and VisualHub seems to do everything flawlesly.
If you are using Windows there are a number of programs to use, when I had Windows, I used ImToo products for video conversion. I haven’t found one good program for Windows that lets you convert all file types however. If you know of any other good programs, let me know.
Once the MP4 is created, the program will either automatically add it to your iTunes library or you will have to add it youself. The final step it to connect your iPhone, click on the videos tab, and sync. Then you can watch your movie in the iPod app on your iPhone under the videos tab. This also works for the first generation iPhone and the iPod touch.
Also you can see the Video Presentation on How To Add Movies To Your iPhone 3G.
Reported by eHphone.ca