This may seem rather delayed considering CS5 has already come out, but I know many of us are a little behind on updating. I was ecstatic when I finally learned how to package Illustrator files in CS3, but recently found out that it doesn’t work the same way in CS4. This sent me on another mission, though a much quicker one, luckily. Thanks to Google + Real World Adobe Illustrator CS4 by Mordy Golding, I got an answer.
Here’s how you collect for output in CS4. First, find the collect for output script in Applications > Illustrator CS4 > Scripting > Sample Scripts > AppleScript. Then, drag a copy of it to Applications > Illustrator CS4 > Presets > en_US > Scripts.
Restart Illustrator if you had it running. Once you get the program started, you simply go to File > Scripts > CollectForOutput. It will ask what file you want to package and where to put the resulting folder. I actually like that they changed it a bit so now it can live in the menu.
I did a little more browsing around, and it looks like this approach also works with CS5. Please let me know if anyone finds out different. Also, this still does not collect fonts, only images.
UPDATE: We now have confirmation that this method definitely works in CS5. Thanks Nick!