prototype archives
I appreciated both 37Signals and Jeff Croft’s take on why and why not to use Photoshop or a visual comp as part of a prototype workflow. Jeff makes excellent points that established patterns, maturity of a product, and the client’s ability to visualize all influence the need for or lack of a high fidelity visual prototype.
ModalBox is a cool javascript/ajax modal dialog library that uses Prototype and Scriptaculous. Very cool Mac style popups and forms (and no iframes!).