Okay....so, I am late, but this does come as a great news. I wrote a lengthy piece on this on my external blog.
So, yes. This piece of legislation applies to the whole country. The Supreme Court, in a ruling in 2006, has given power to all High Courts to 'expand' their jurisdiction in cases pertaining to Parliamentary Laws. Since the IPC is a nation-wide law, it falls into this category.
Also, since the Supreme Court itself asked the Delhi High Court to look into the matter, it is understood that the legislation applies to the whole country. Lastly, as this is a first in its case, there is no precedence for such a ruling. Hence, it HAS to be applied to the whole country.
Section 377 still remains in the rule-books and it will continue to do so in the near future, judging by what the government is saying. It is only the interpretation of the law that has been changed....to not include consensual same-sex.
Hopefully, this is the start of something new and positive for the Indian Gay Community....
Ciao
BeaStKid