15 October 2008
UPDATE
Put the tango folder into (default for Windows) C:\Program Files\FileZilla\resources\
Select Tango from the drop down menu in the FileZilla options.
Enjoy!
If you want 32x32 and 48x48 icons let me know and I'll probably update the skin

<?xml version="1.0" encoding="UTF-8" standalone="yes" ?>
<FileZilla3>
<Theme>
<Name>Tango</Name>
<Subdir>tango</Subdir>
<Author>~sumowski</Author>
<Mail>sumowski.deviantart.com</Mail>
<size>16x16</size>
</Theme>
</FileZilla3>
This will let you select the Tango theme in the settings dialog.