Hi Lee:

This could be caused by a variety of things, depending on whether your project properties and/or render settings are set correctly to whether you are playing interlaced video on a progressive player.

For now let's assume it's because you have interlaced footage on a progressive player. As you may know, your computer screen and flat screen TV is progressive. Ye Olde Tube TV is interlaced. Many flatscreen TVs have software to handle these sorts of things, but some of your computer playback devices may need a manual tweak to play the footage nicely.

So I took a look at Windows Media Player, and I don't see a setting to control interlaced versus progressive play. It may be there, but I don't see it.
I don't use WMP except for playback of DVDs. It doesn't like my HDV footage raw or rendered . . . the playback can be jerky and jaggie.

I use VLC Player (free download from CNET.com). There is an interlaced versus progressive setting in VLC Player. When I play my interlaced footage in VLC Player, I see "jaggies," but these go away when I set the interlace mode in VLC Player.

Have a look at these options and see if that resolves your issue. If not, you may need to post again with your project properties, the kind of footage, render settings, etc. to get a solution.

Happy Thanksgiving!

Kimberly