Okay, so you know that windows iPod's support MP4, but how do you get this to work.

First, Lossy formats causes your converted music to degrade in quality where lossless formats don't loose quality when ripped from a CD.

To start of, IT IS NOT WORTH transcoding your MP3's to MP4, coverting from one lossy format to another will just degrade the quality of your music much more, just re-rip your CD's it will
be worth it in the long run.

I suggest you use a lossless format to start with when ripping CD's, like Monkeys Audio which compresses at a ratio of 4:1 at best and does not loose quality when ripped from a CD.
Then you can convert the Monkeys Audio files to MP3, MP4 or future codecs and you can play with different setting and find the best quality.

AAC (Advanced Audio Coding) is technically superior to MP3, with better quality and smaller file size. The MP4 was born.

128k AAC MP4 has had good receiption, with good quality and good file size, personally I am happy with the quality of 128k MP4, and found it to reduce the size of my Music collection on my iPod.

Okay currently there are two programs i have tested that work with MP4 files:

Ephpod 1.70a
Sveta Portable Audio (dBpoweramp)

There is no tagging standard at the moment, and Ephpod does not support any tagging, so if you transfer MP4 files using Ephpod you will have to manually tag each file which can be very time consuming.

I suggest you use dbPoweramp at http://www.dbpoweramp.com

It supports tagging with MP4's, obviously only if you use the bundled CD ripper, which is a good quality ripper to rip CD's to MP4.

I have used all the programs for iPod, and tested all the different MP4 encoders.
I've found that dBpoweramp and Sveta Portable audio available from dBpoweramp (http://www.dbpoweramp.com) to be the best.
It supports practically ALL codecs, has a great ripper and Sveta works great with iPod.
It's support for Tagging makes it desirable and software support and updates is great.

I hope this is of help as i have found little support for windows MP4 users.

dBpoweramp (http://www.dbpoweramp.com)

If you have any comments message me on AOL my handle is craigcullum