One of the holes in Automator's action lineup is an action which will delete files -- not move them to the trash, but actually delete them altogether. So I decided to write an action that does just that.
Delete Files.action is an open source (Lesser GPL licensed) program that provides an Automator action that shows up in the Finder entry in the Library column, and accepts "Files/Folders" as input. One can select from four delete types (simple unlink, 1-pass wipe, 7-pass wipe, 35-pass wipe), can instruct it to ignore errors, and can customize the optional confirmation dialog.
The action is free to use; feel free to comment on it here or drop me an email...
[robg adds: I tested this out, and it works as described. After installing the new action, you'll find a folder on your desktop with three Automator plug-ins for the Finder. Drag some/all of them to you user's Library -> Workflows -> Applications -> Finder folder, and you'll have them available in the Finder's Automator contextual menu. This code is also a great way to see how to create an Automator action of your own, as the source is included, so you can take a look at the AppleScript that drives the action.]
Mac OS X Hints
http://hints.macworld.com/article.php?story=20050910203526976