Biggest difference between the two is that there is no "flow" in Bikram. None. Half is the standing series, half is the floor series, all of the Bikram poses take short standing or lying "rests" between asanas.
Bikram's is 90 minutes. There is no short version.
As far as I know, there is no DVD of Bikram's series, only audio CDs and the book.
I would highly suggest attending a class or two of Bikram's before purchasing anything, people either love or hate it.