I have no tried this yet but I work it out for other uses, try going into iTunes folder on your pc might be located in music in windows, click on that and you will find music folder again, click on that and there must be a list of your mp3s from here on just drag and drop to your mp3 player make sure it does just relocate it copies.
In some cases yes. If you've ripped the CD onto your computer then there is a button under....file or edit...one of those options at the top. It says Convert to MP3. But in order for that to happen you have to go to your Preferences and tell iTunes to import as MP3 and not AAC.
If you bought the music from iTunes you can't unless you burn the music to a CD and then rip it into your computer as an MP3 using windows media player, or other inferior software (you can do it with itunes but it's kind of pointless in that case).