How to make a directory listing (preview) with PSD files ?

Depending on what version of Photoshop you want this for, it may not be possible. It seems to me the ScriptUI is the most buggy part of Photoshop scripting and what you can do( both because of the bugs and because of added features ) varies a great deal from version to version.

It's also going to be a complex task and one I have not seen posted here or at PS-Scripts. You may not be able to find a fully working example of what you want to do. The link JJMack posted should give you an important piece. It shows how to use Bridge to create the needed thumbnails. But as noted in that thread not every script posted there will work in all versions. Some crash Bridge CS6 but work fine in with Bridge CS5.

Did you do a search before posting this question?

If you did you should have found threads on that subject like http://forums.adobe.com/message/3535290#3535290

The Paul mentioned has left this forum and taken down his Photoshop scripts web site because of Adobe behavior of not fixing bugs and starting CC.

Paul Riggott we are missing you