It's a sign of our times. Indian English follows more or less the British pattern (colour instead of color etc.). However, recent times have seen a marked shift towards American spellings and pronunciation. I would imagine this is the case in other former British colonies as well.

As long as they keep reading P.G. Wodehouse...

It's because of cultural influences such as Hollywood.

Oh, I understand why it is, but it doesn't stop me complaining :-)

I'm starting to feel some sympathy with the Academie Francaise [1]. At least the US English <--> British English traffic in terms of idioms isn't all one way [2]

[1] http://en.wikipedia.org/wiki/Acad%C3%A9mie_fran%C3%A7aise

[2] http://www.bbc.co.uk/news/magazine-19929249