Irrelevant to the Presidency (otherwise Schwarzenegger could become President). Obama must be both a citizen and born in American territory.
Where do you see that in Article II?
http://en.wikipedia.org/wiki/Naturalization_Act_of_1790
"The Act also establishes the United States citizenship of children of citizens, born abroad, without the need for naturalization, "the children of citizens of the United States that may be born beyond Sea, or out of the limits of the United States, shall be considered as natural born Citizens"."
If his mom was a citizen, he is considered a natural born citizen no matter where he was born.
Neither of Schwarzenegger's parents is a US citizen and he was not born in the USA.
His case is completely unrelated.