Hydrogen fueling stations have not been standardized yet though there is a push to do so in order that hydrogen autos may start to rollout commercially within the next 5 years. On the California Fuel Cell Partnership (CaFCP) website there are a couple of pages outlining what the current hydrogen fueling stations look like and how they work.
Some of the hydrogen fueling stations in California are prototypes used as demonstration models and thus not open to the public. However, there are also some hydrogen pumps such as the one in downtown Los Angeles at a Shell station that sells retail hydrogen to the public.
CaFCP lists three different types of hydrogen fueling stations including those that create their own hydrogen onsite, those that have hydrogen delivered in liquid form and those that deliver hydrogen as a gas. There is also a fourth type of station which is a mobile hydrogen refueler which can easily be moved from one location to the next.
In regard to those stations that create the hydrogen onsite there are also a couple of types. The first type uses electricity to split water into hydrogen and oxygen, then captures and compresses the hydrogen for use in autos.
The second type uses natural gas and reforms this into hydrogen which can be used to refuel autos as well as heat the home. Check out this link and this link from the CaFCP for more details.