The day has come. jQuery Impromptu is changing the face of ajax forms as we speak. Plain Jane prompts and dialogs are a thing of the past. jQuery Impromptu 2.0 now introduces "States" to have multiple forms with in a prompt. For instance an installer, you click Forward, Accept, Forward, Install all within the same window. Now you can have the same functionality easily with Impromptu. Take a peek at this video demonstration:
Please pardon the poor quality, hopefully I'll get a better video shortly..