I think Mumsnet should support this campaign.
I do agree with a previous poster though that we should be lobbying governments to make the 'code' a legal (and enforced) requirement in every country. Its staggering that such an important issue is often left up to the discretion of the companies, who will [grudgingly] abide by aspects of the code enforced in one juristiction whilst blatently breaking it where it thinks it can get away with it.
It is not just women and babies in the developing world who are let down by unethical marketing. We might think ourselves sophisticated enough to ignore it and think that the public health messages counteract it, but many more women have difficulties breastfeeding than should physiologically be the case. We're still suffering from the lack of breastfeeding knowledge from the generations who were encouraged to bottlefeed. A large part of the problem is people not knowing what is normal infant nursing behaviour is, and our modern tolerance for neediness in our babies is unrealistically short.
I think a clear warning that if mother's are having problems breastfeeding that they should contact their midwife or one of the genuine helplines for advice because giving formula could interfere with their ability to breastfeed successfully.
To be honest, I think in this country we actually have pretty good numbers of women who want to breastfeed, I think we need to back it up with practical support, in person in those first few weeks, 24 hours if possible. I had a few tricky moments in those first few days, but my local midwives were very approachable and helped me through them. Better support might help women who want to breastfeed do so, and reduce the number of women panicked into using formula because they can't get baby latched on at 3am when their milk comes in.
Something odd happens with the right wing media here btw. If there is a hint that a product could possibly reduce the risk of cancer by a tiny bit in a limited study, it's headline news. But if not using a product could reduce the risk of ovarian cancer by a significant amount, its sidelined behind a bunch of articles about how its our choice to formula feed and how the benefits of breastfeeding are exaggerated, and how its such an imposition on a mum to nurse her baby and on businesses to enable her to express when she returns to work. 
I'm asthmatic and have hypothyroidism. I rely on the products of large pharmacutical companies. I still think they can be extremly unethical and wish governments would make them behave more ethically. I don't see attacks on big pharma to be an attack on me as a (somewhat) ill person. I really wish mums who need to (or choose to) formula feed could see that it would benefit EVERYONE if they were made to be honest about their products and stopped unethical promoting/advertising.