Which patents were involved in Apple v. Samsung? addresses a lot of design patents. Is there an online repository of design patents we can link to?
Like Luis said, Google Patents has them. Just make sure to format the number as "USDXXXXXX" (e.g., USD504889). You can also use the PTO's search using the format "DXXXXXX" and then clicking on the "Images" link on the page containing the specification (warning: their imaging tech is extremely outdated, I think you need Quicktime (!) or another TIFF plugin viewer since it's an element).
Google patents has only US design patents. Most of countries have their own patent and registered design databases. For example here is German desings database: http://register.dpma.de/DPMAregister/gsm/einsteiger There are also some regional design systems. For example here you can search European Community registered designs: http://esearch.oami.europa.eu/copla/advanced#/designs And here is search tool for international registrations of industrial design: http://www.wipo.int/ipdl/en/hague/
Google patents has at least some design patents; not sure if it is complete or not.