Fact: Wilders wants to the Quran to be forbidden.
Mein Kampf is banned in Germany, what's the difference?
Technically, it isn't banned.
The state government of Bavaria, which is holding the copyright to "Mein Kampf", just isn't allowing any reprints. This has something to do with Munich still being Hitler's official place of residence at the time of his death or something like that. When he died and the German Reich ceased to exist, the copyright first fell to the American occupation authority (since Bavaria was part of the U.S. occupation zone). With the end of the occupation, the state of Bavaria finally inherited the copyright to "Mein Kampf".
Since that time it has been the policy of the Bavarian government not to allow any reprints of "Mein Kampf". This also means that it is legal to own, buy, and sell issues of "Mein Kampf" which were published prior to 1945. Strictly speaking, surviving relatives of Adolf Hitler also could have gone to court and reclaimed the rights to "Mein Kampf", but nobody from the Hitler family actually tried to do this. Currently, the copyright is expected to expire on December 31, 2015 (= 70 years after the death of the author). On this date, "Mein Kampf" would enter public domain.
Aside from Germany, the state of Bavaria also owns the copyright for "Mein Kampf" in a number of other countries and is using it there to prevent the book from getting reprinted too. Among the countries where it is allowed to publish "Mein Kampf" is the United States. In this particular case, the copyright to the book was seized by the U.S. government during World War II under the so-called "Trading with the Enemy Act". Otherwise, the copyright for the United States would probably be in the hands of the Bavarian state as well now.
The author of the Quran has been dead much much longer than just 70 years, so the same thing clearly couldn't be applied here.