Firstly The 16th Amendment was not properly ratified. Please see

http://www.thelawthatneverwas.com/new/theman.asp

secondly even if it was ratified there are eight supreme court rulings that said the 16th amendment gave the no new powers to tax. They include

Brushaber v. Union Pacific Railroad Company

Staton vs Baltic oil

and lowe vs peck

and have never been over turned

These court cases caused the demise of the income tax law passed in 1913

Also , Income as defind by the constition is

gains or profits made by corportion

For a good documentry on this subject check out

http://video.google.com/videoplay?docid=-1656880303867390173