Using psd2css online is simple. Here are some tutorials to get you started:

Tutorial 1: The Simple Example
Tutorial 2: But I need text in my page! (updated video tutorial)
Tutorial 3: The Gimp and layers named '_text' (video tutorial)
Tutorial 4: More Control By Naming Your Layers
Tutorial 5: Make Links and Buttons with your Layer Names (video tutorial)
Tutorial 6: Image Rollovers for your Links (video tutorial)
Tutorial 7: Forms and Centering your webpage (video tutorial)
Tutorial 8: Menus! Create working animated menus without writing any code (video tutorial)
Tutorial 9: Web Pages that expand with your text
Tutorial 10: Floating DIVs - Wrap your text around some images New!
Tutorial 11: Use '_basename' to create reusable components for your web pages New!

Here are some examples:
http://psd2cssonline.com/tutorials/menu2/index.html
http://psd2cssonline.com/tutorials/page1/index.html
http://psd2cssonline.com/tutorials/template/index.html
http://psd2cssonline.com/tutorials/forms/index.php