Burning iDVD output on a PC

Yes if PCs can recognize the .img extension (but I don't know if they can). Otherwise maybe Toast could convert an img to an iso or something (I haven't tried this though).

I think a PC should. Since all DVD/CD's are based on a similar file system, i guess it comes down to the PC counterpart. I know Nero on the PC side can read .img just fine (accompanied by its respective .cue file of course).

As far as I know, iDVD's only output is to burn to DVD. Either that or save it in their format (.dvdproj I think) and take it to another Mac with a burner.

Get the iDVD 4 "burn to external drive" hack. Once you have that, if you either command click or option click (can't remember which) the burn button on your Mac it gives you the option of burning it to an image file. It saves the file as a .dmg file. Rename this file to .iso and you should be able to burn it with your PC.