Wow. That's a good deal.
What it really means, of course, is:
"We can't sell our tethering package, so let's try rolling it into the home broadband package and see if we can sell it that way."
That said, O2's home broadband packages are some of the best deals around, and this just makes them better.
For me, though, it won't be enough. I can't get a signal from any network inside my flat, so Vodafone's femtocell is the deal-breaker. If only O2 would reconsider...