This tutorial will cover exporting using our recommended YouTube settings using iMovie and Final Cut Pro.
Exporting using iMovie
When you are finished with editing your project, first save your project and then choose File and click Export.

In the window that appears locate the drop down menu beside the text that says "Compress Movie For". Choose "Expert Settings from the list.

Choose a place to save your movie and then click on the "Options" button.

At this point the steps are the same for both iMovie and Final Cut Pro. Skip down in this tutorial to the section labeled Export Settings.
Exporting using Final Cut Pro
When you are finished with editing your project, first save your project and then choose File, choose Export, and then click on Using Quicktime Conversion.

Choose a place to save your movie and then click on the "Options" button.

Refer to the Export Settings section below to proceed.
Export Settings

In the window that has appeared, first click on Settings under the Video category.
Choose "MPEG-4 Video" from the drop down menu labeled "Compression Type" and adjust the Compressor Quality scroll bar to "High" and click OK.

Now click on Size under the Video category.
Use the drop down menu labeled "Dimensions" to choose the "Custom" option. Type "478" and "359" into the two boxes to the left of the drop down menu and click OK.

Click on Settings under the Sound category.
First, click on the Format drop down menu and choose "AAC". Then click on the Channels drop down menu and choose "Mono". Finally, click on the Rate drop down menu and choose 44.100 khz. Then click OK.

Now UNCHECK the box beside the Prepare for Internet Streaming category. Click OK and then click Save and wait for your video to be exported so that you can upload it to YouTube.