Everyone knows that, when starting out a new web project, you should do some extensive prototyping. Sketching your interface on paper, using the lowest level of detail possible, is a very good idea, mainly because it lets you quickly see the bigger picture as well as conduct some informal usability testing, without getting bogged down by the finer points of your design.
I’ll admit that so far I haven’t really been practicing what I preach. I find drawing on paper somewhat cumbersome, and it doesn’t really give me the flexibility I need to do changes, both big and small, without having to redraw the whole thing over.
Enter Mockups, a web/desktop application made by Balsamiq. It presents you with common web application interface elements, allowing you to drag and drop them around a stage in order to build prototypes. Unlike with actual pencil drawing, you can make changes really easily, and create sketches that are more accurate and actually good looking. Another cool possibility Mockups gives you is the ability to easily share your creations, and let other members of your team write comments, make changes or suggestions to your prototypes. The full version costs $79, but you can use a version with less features (such as saving) for free. Also, if you ask nicely enough, the authors just might give it to you for free. Try it out now!