The advertising point of the new iPhone 3GS are the video recording, faster and longer battery life. The 3GS is a nice step up. The “S” could represent several elements, such as snapshot with clearer image, software update with better integration, speed for better processor.
You can use an extra tool to solve this problem. Its name is 4Videosoft iPod to Computer Transfer.

Best DVD to iPhone Converter to convert AVI, MPEG, WMV, MOV, ASF, QT, MOD, DivX, XviD, MP4, VOB to ipod video format, a multifunctional tool, which does not only convert DVD to iPhone formats but also edit the output.

I have been using it for a period. It helps you transfer music, songs, videos from iPod to Computer directly when you want to backup your iPod files to Computer.
You can free download it on the following website to have a try.
Hope my advice can help you.

Pavtube MTS/M2TS Converter for Mac is a marvelous conversion software.

Transfer iPod/iPhone/iTouch stuff to computer or recover lost or missing music, backup and restore all of iPod/iPhone/iTouch content I recommend you Cucusoft iPhone/iTouch/iPod to Computer Transfer. This software can keep your iPod/iPhone safety.
Best iTunes/iPhone/iPod Transfer for Windows and Mac Review:
Step by step guide– How to transfer music/movie from iPod to computer or iPod to iTunes with iPod Transfer?
Also, you can search some other ones:
hi here you can have a try Aiseesoft iPod to Mac Transfer
it can help you backup the files on your iPod to the local disk of your Mac
for more details you can goto
hope it is useful
and there provide a free trail so just have a check first
Try this iPod to iTunes transfer program
It was designed to help transfer music, videos, photos, playlists, podcasts and more from iPod to computer and iTunes. So you can use it to transfer music from your iPod back to your iTunes in a direct way. Then all files are on your iTunes, and you can sync smoothly without deleting any files.
This is easy and quick. I recommend you use it.
Free Download to try
Best luck!

MKV Converter for Mac provides powerful edit functions, such as trim video, crop.

I think you need to convert the avi files to mov or mp4 formats so that the videos can be directly played by imovie, perhaps you may give a look at this mac video converter, it’s really a good one for me to convert all my video files, with simple process and powerful functions.It can support many input and output formats, you may like it as i think it’s really a good one for you to convert video files