This is an undocumented tool in Wavosaur, it can be useful :
go to “Tools” menu and select “Note frequency calculator”
this simple windows shows up :

Select the note in the drop down list, the octave and the alteration : none, flat or sharp.
the “Hertz” textfield will give you the frequency value for the traditional Western music scale.

Another useful thing is this midi note hex values array : http://www.wavosaur.com/download/midi-note-hex.php