I've exported HDV footage from Final Cut as quicktime files (not self contained), and brought that into iDVD for burning. I noticed while previewing some of the clips from iDVD, that the deinterlacing is really bad with the heavy motion...will burning the DVD fix this or do I need to go back and export my files with deinterlacing check marked?
You will notice the interlacing on a computer. If you burn and playback the DVD on a software player, it should de-interlace when playing back. Playing back on a set top DVD player the picture should look correct as well (so long as bottom field first is used). You can export with De-interlace checked from FCP as well. You will have to see which looks better to you.