1) The "easiest" way to convert those songs to mp3 is to burn an audio cd (cd-rw) is fine the rip back into mp3 format. You'll lose tagging information...you'll still have song titles but you'll probably lose artist, album, and track number information. You can always edit that back in or possibly use a program (I'm not really familiar with these, though).
As for your unprotected songs (which you ripped from your own cds), you actually can convert them into mp3s within iTunes and retain whatever information was already there (including album art, I think). In iTunes, right click on the song(s), then select "convert to mp3." If you don't find this choice, you'll need to change your settings. Go into the edit menu, then preferences, then advanced, then go into ripping and change your settings to mp3 then choose your bitrate. I think this is the way it goes. I'm at work right now and don't have iTunes installed on my computer so I'm doing this from memory. Anyway, this won't delete the original AAC so you'll probably want to delete the AACs off of your hard drive when you're done. Any iTunes Plus (unprotected AACs from iTunes store) can be converted in the same way.
2)You should be able to hook up your speakers through the headphone port on the Archos to the auxillary input on the JBL OnStage (I think it should have one).
3)There is a dock available for it. Like most things, it is an optional accessory. You might be able to find a generic charger for it, though.
I own a 4th generation (non-video) iPod, 40g. Well, my iPod is officially dead and I am considering buying an Archos 605. My main concerns are as follows:
(1) My music is in AAC format, and I've downloaded approximately 200 songs from iTunes and I understand it is in AAC-protected format. I was told I could burn the "bought" songs onto a CD-RW (or several CDs as the case may be) and then upload them on the Archos 605 in MP3 format. Is this correct? Also, what about moving all my other songs ripped from my own CDs--any problems other than converting the format from AAC to MP3? (I utilize Windows PC with XP, btw.)
(2) Can I use the Archos 605 with external speakers? Is there an "out" line (I can't seem to find it on the specs)? I utilize my iPod mainly with speakers, not with headphones. I use a JBL OnStage to listen to my iPod and it's been wonderful, and must have the ability to hook up speakers to the Archos 605.
(3) Does the Archos 605 use a "dock" or is the only way to charge the device through the computer?
Please let me have your advice. Thank you. Roberta