"one nation, under GOD"...
wasnt the first big idea to have a seperation of church and state???
The pledge itself is neither constitutional nor unconstitutional. People can pledge allegiance to whatever what they want to. On the other hand, forcing
people to say the pledge is unconstitutional because it violates their freedom of speech, whether the "under god" part is in it or not. In between, you have edge cases like the ones in the lawsuits mentioned in earlier posts. They deal with schools that led a reciting of the pledge, encouraged the students to participate, but didn't force them to. That's the kind of cases on which federal judges can disagree.
Personally, I find the pledge distasteful with or without god in it: Republics and their flags are mere tools through which people secure their human rights. Therefore it's unbecoming when a republic promotes itself to its citizens as an object of worship. That's why I intend to say the pledge exactly once in my life, immediately after I get my US citizenship. And even then, I do not intend to say the words "under god".