I love design patterns -- it is a great way to communicate among developers about the nature of a given problem area and what is likely to work or not. By using patterns, developers don't have to recreate the wheel each time.
The folks at infragistics have put together a UX Patterns site that is focused on share patterns in the UX space. Just as with code, using existing patterns can help you consider options, pick among standards and avoid recreating the wheel each time.
Use and Enjoy!
BTW, in case you think applying the "patterns" concept to the UX space is stretching it, keep in mind that the roots of the term are in architecture.. check out one of my favorite books A Timeless Way of Building.