Just came across a better article that explains the wmode in greater detail.
http://kb.adobe.com/selfservice/viewContent.do?externalId=tn_14201&sliceId=2
and
http://kb.adobe.com/selfservice/viewContent.do?externalId=tn_15523&sliceId=2
Please note that there seems to be a performance issue when using the wmode based on viewing.
Bruman
