Resolution: I don't understand something, please explain.
 

Commercial SD DVD movie is MPEG-2.
For burning my home movie project, I of course selected MPEG-2 as well.
Why is it that when I play the commercial DVD movie, blown up full screen on a 28" monitor (1920 x 1200), I don't see jagged edges. However, when playing my home made DVD, there are jagged edges. Both DVDs are 720 x 480, right?

Thanks,

You might get jagged edges depending on how you downconvert your material.

The MPEG2 encoding may also introduce stairstepping.

What is your source material?

If source material for your home DVD is interlaced (like 60i footage from a miniDV camera) then you'll see jagged edjes on computer monitor which is a natively progressive device, unless de-interlacing feature is enabled in your software DVD player.
Commercial movie DVDs are made of progressive material (film) so there is no interlacing artefacts while playing them on PC.
Maybe this is your case - interlaced vs de-interlaced source on progressive display.

The source material is HD from a Canon HV10.
Thanks,

I played the home DVD using 3 different applications: Nero, Window Media Center, and Windows Media Player. Do you know if this "de-interlacing function" is available with what I have? What do YOU use to play your home DVDs?

Thanks,

I rearly play DVDs on computer (normally on a standalone DVD player) but when I do I use PowerDVD, it de-interlaces video by default. Windows Media Player de-interlaces by default too. I'm not familiar with other two you mentioned but I can also recommend VLC player with the most extended options for de-interlacing.
I didnt realize you had an HD source. This might be downscaling distortions then, nothing to do with de-interlacing. It's hard to say though without seeing the picture.