Note 78: Support for the PNG format in Delphi is available using the free PNG Components (http://www.thany.org/article/32/PngComponents). This library has even a custom ImageList that makes PNG images available to buttons, menu items, and the like.
This blog post is part of my "113 Delphi 2007 Handbook Notes" blogging project, to promote my new Delphi book.
Update (Jan 14th)
As some blog readers pointed out (see below) the URL changed to http://www.thany.org/article/18/Delphi_components and these PNG components seem not to be in a very good shape. Alternative proposals?