Fear not, you can still use your iRiver and your Mac. What you need to do is get your iTunes selection into MP3 format by doing the following.
In iTunes Preferences, go to Advanced, then Import. Select Import Using MP3 Encoder.
Then in iTunes select in the Playlist(s) the songs you want to put onto your iRiver. Then go to Advanced (in the Menu bar) and on Covert it should show MP3. Click on it and it will then convert your selection to MP3 which will then be compatible with your iRiver. It won't delete your original AAC tracks, just make duplicates in the MP3 format.
That, however, will only work for tunes you have imported into iTunes from audio CD. The method for converting songs bought from the ITMS is slightly different.
For those you will need to burn an audio CD, the add it to the iTunes Library as an MP3 file (using the same instructions as above). Messy, I know, but it's the only method that works as you cannot download any purchased iTunes music in any other format than AAC.
Hope this helps
Cheers
NikkiG
