In meaning, 'though' and 'although' are very close but as Kenny's link suggests, they aren't quite interchangeable. Although is seen as more formal and more likely to appear in writing while though you will hear in speech more often. Also, because although comes at the beginning of the sentence, people who are just talking are more likely to use though when they get to the end of their point. You can only use although when you know what idea you are trying to convey at the start of your speech. Hope that helps.

Please read this : http://gmat-grammar.blogspot.my/2006/06/although-vs-though-vs-even-though.html