Okay, here's what to do.
Forget all the exporting as dv or quicktime and import to iMovie, yada, yada, yada.
Go into your project in FCE and right click in the Bin and create a new sequence. Right click on the new sequence icon and go to sequence preferences. In the preferences, you will see a list of settings, look for one that says the ratio of video. It will most likely be set to Anamorphic 16:9 (because of your anamorphic video). I believe the setting are changed by going thru a drop-down list, use the list to find the ratio of 4:3.
Once you have found this, accept it, and accept the sequence preferences.
Make sure your new 4:3 ratio sequence is open, and click and drag your Anamorphic sequence (the one you were trying to export) into the timeline of your 4:3 sequence.
When you have done this correctly, you will notice that FCE will automatically set the old anamorphic widescreen sequence to fit the new 4:3 full screen sequence. Render if needed.
Export to Quicktime with desired quality.
Send to iDVD make sure iDVD is set to Fullscreen (4:3) not Widescreen (16:9)
To summarize what you did here, since iDVD cannot read Anamorphic widescreen correctly, you have mimmicked the look of widescreen my "letterboxing" the anamorphic into the new sequence. iDVD now does not have to think of trying to set it to widescreen or not, but just knows it's regular 4:3 footage.
I hope this helps!
