The source code for Toucan, 7-Zip and BURP are available from the Toucan homepage:
http://portableapps.com/Toucan

All of the icons apart from the 'Add Portable Variable' icon (which is a mash-up of two of the other icons) are Copyright Silvestre Herrera and are from the Dropline NEU icon set which is also released under the GNU GPL2 see them here:
http://www.silvestre.com.ar/