Hydrogen fuel stations

According to the June 2005 issue of Road & Track:

A million a pop for hydrogen stations? That doesn’t seem too bad, considering that an infrastructure will promote the develoment and manufacture of more fuel-cell vehicles (FCVs) and should make the stations profitable somewhat quickly.

Questions: How is hydrogen actually gotten from petroleum? Is it more efficient to extract the hydrogen and use the rest of the petroleum for something else, or to just use the petroleum as we always have? What would it take to extract enough hydrogen from non-petroleum sources to supply a growing number of FCVs?

I’m not sure about extracting it from petroleum but its easy enough to extract it from water using electrolysis. I do know it can be extracted from petroleum I am just not sure how its done or how energy efficient it is. Its my understanding that electrolysis is not all that efficient a process, but it does let us get the power from other sources like hydroelectric, coal, or nuclear,