iPhone 3GS - must have OS 10.5 and above to get music on it?

Greetings,

I just got my first iPhone, and I love the device (iPhone 3GS). The trouble is my two Mac computers are a bit long in the tooth and only run OS 10.4.11 (iTunes 9.2). The iPhone won't show up on either desktop or in iTunes because it requires 10.5 and above.

I want to get some tunes onto it for listening and ringtones and all that jazz. So, I added the dropbox app since I use it on my computers, but there doesn't appear to be a way to drag anything out of dropbox and into the iTunes on the iPhone. I tried emailing songs to myself as attachments, but I can't seem to get email attachments onto the iPhone either.

It's a silly complaint, I love all the other stuff the iPhone does. I have Pandora on it so I can play music whenever with it. I own two other iPods so I can use those to satisfy my control freak tendencies. It's just a tad annoying, I want to use this one track for a ringtone, and I'm not about to pay for it again just to have it in the iPhone's iTunes.

I'm due for a new laptop and when I make that purchase it will surely rectify these problems. After that I'll probably upgrade to the newest iPhone. Just irritating little cases of planned obsolescence. My poor old Macs, still kicking butt since I keep their hard drives nice and empty, are going the inevitable way of the dodo...

Am I wrong and there's a way?

Thanks in advance,
Jon