It's not quite that easy and I wish I could type fast enough to write a decent response before every nimrod on gfy breaks this down to a "Fuck Jews / Fuck Arab" type thread.
So instead of typing:
http://en.wikipedia.org/wiki/Israel
It's a good article that covers the basics. More or less Jews have been in this area of the world though for a really long time. They got kicked, came back, and there's been Jewish settlers in the area long before WWII.
It's not such a black and white issue that people like to portray...especially the whole Jews stealing land, etc, etc, honestly the Jewish state would have been tiny, a spec on the map, if the Arabs could have just settledown and let it be.