At this stage, little is known of the scheme other than the headline budget (one presumably set simply by taking the cost of London's £23m Millennium Bridge and adding on a few bob for inflation), the likely bridge alignment, and that the contest will be properly launched in late 2013. The scheme is being promoted by Wandsworth Council and presumably their fellow members of the Nine Elms Partnership. There are a few initial images available in a planning document, which I've pilfered for this post (click any image to see it full size).
The naysayers have already planted a stake in the ground. Last August, London's Evening Standard newspaper managed to dredge up at least two locals who would offer a quote opposing the plans.
This isn't the only current scheme for a new footbridge in this corner of London. Roughly two miles further west, there is a proposal for a £22m span, connecting Chelsea Harbour on the north bank to Lombard Road on the south bank, close to Cremorne Railway Bridge. Images of this proposal were made available in November last year (see video below), and it has been submitted for planning consent by designers One-World Design (Expedition Engineering helped develop the proposals). The planning committee is due to consider it in April.
This one has no funding in place and has been dreamed up by the designer rather than the local authority. They hope to find a private sponsor to pay for it. A bridge had been considered at the same site in 2003/4 to offer a good ratio of benefit to cost, but had failed to progress then due to lack of funding. I predict a similar fate this time around.