Setting Transparency

[JohnHuff]

How do I change the transparency (opacity) of a polygon graphic that I've filled with a color?!?

And yes, I'm new to ESRI/ArcGIS products...

[TimothyHales]

I am not sure you are able to change the the transparency in ArcGIS Explorer. 

That functionality is not currently available in ArcGIS Desktop. You can convert the graphics to features and then apply the transparency to the new layer.

Converting graphics into features