how to burn iDVD without a superdrive

You would need to buy an external burner. There are lots of them out there that are compatible with the Mac. I think that LaCie makes one. It should be connectable by firewire.

Not sure whether your PC burner would work. You can try it by first saving your iDVD project as a Disk Image (an option in the iDVD File menu), and then transferring that Disk Image to your PC and see if you can burn it. I have never tried that myself, so can't vouch that it will work.

Rich's disc image option is a good one (there have been some reported file format problems, but try the disc image solution). An external drive or a replacement optical drive for your Mac are both reasonable alternatives. Another type of option is a VideoCD - it puts your video onto a CD at roughly VHS quality. These VideoCDs were very popular is Asia and other places and many DVD players in the US also can play them. The obvious tradeoff is lower image quality and shorter productions. Roxio Toast (for the Mac) can create these -- here's what they say:

"A Video CD holds approximately 60 minutes of video or slideshows and
offers good quality, but menu navigation is limited. This CD can be played
in most set-top DVD players. Consult your DVD player manual to see if it
supports Video CD playback. This is the best choice for a video disc if you
only have a CD recorder in your Mac."

Toast can also do Super VideoCDs (20 min max).
John

Did you find transferring it to your pc worked in burning your dvd? I'd like to do the same. I don't have a superdrive either. Just wondering if their advice worked.