How do I make a generic audio CD with Apple iTunes?

It took me a few days and some discussion with a Mac guru pal to see the problem in what you've explained here: when you "transfer the songs" in iTunes, I'll bet that you aren't specifying that you want an "audio cd" format disk!

When I make audio CDs, I use Roxio Toast Titanium 6, which is a wonderful program but basically vast overkill for a party dub, and at $75, kinda steep too. It works great for DVDs too, but that's another story entirely!

Anyway, back to the problem. It turns out that iTunes has the ability to burn data disks or audio CDs, and you need to pick which one you want by going into your Preferences within iTunes and clicking on "Burning". You'll see a dialog box similar to this:

As you can see, I've already selected Audio CD as the default format for a burn. I'm betting that you have one of the other formats checked as your default, so change it to Audio CD and click "OK".

With that change made, the CDs you burn from this point forward should work just fine in your car stereo, home stereo, and other computers.