It turns out that on converting, the DNG files are saved in the same directory as the source CR2 files and the only way to move the CR2 files is to highlight each one separately. And I do not think that Leopard allows sorting by file extension type. Obviously a royal pain.
Okay, the Finder isn't exactly the best user interface for handling files ever invented, but it
can make these things just as easy for you as in Windows Explorer.
First, open the folder with your files:
[attachment=9841:Finder_1.png]
Then, select detail list view:
[attachment=9842:Finder_2.png]
And finally, sort by file type ("kind"):
[attachment=9843:Finder_3.png]
Command+z for undoing your changes works, too.