3GP is a video file format that is output by certain mobile phones.
I have been battling this one to the point where I built up a quad-core system with 4Gig of ram, nVidia 8600GT, dual monitor, Vista 64bit and 3 separate hard drives. It was still estimating 17-20 hours to render a 3 minute music video with a lot of cuts, fades and layers.
Even if you throw all the power in the world at an application like this, you really need to understand what your computer is doing behind the scenes and find out what is interfering with the slowest part of the process, the I/O.
There were 3 things that really sped up my rendering times:
1) Render to the same settings as your project settings (i.e, if your project is set to 1920x1080x32, 23,976p - then render to an output of the same settings)
2) Stop unnecessary processes, you can download and use a program called 'Game Booster' which frees up your CPU and RAM usage by doing this.
3) Try not to render to the same drive that your originals are being read from.
My rendering time went from 17-20 hours to 20 minutes for a full 1920x1080 - 3.5 minute music video shot on multiple Sony HDR-SR11 cameras, with Chroma keying, fades, masks. On my system, it utilized about 30% of the quad cores capacity and at a max 67% of 4Gig of RAM.
I believe a company called Alias invented the software program.
It depends on the context. Many people will swear by one codec or another, but it really just depends on what the situation calls for.
Nowadays, for the web flash video is pretty much the standard. Flash 8 (On2 VP6 video codec) provides better compression (more quality for lower bitrate) so use that if you can.
If the video is for desktop use then the H.264 is becoming the standard.