Stu is right, MG Rover and the longbridge facility et al.. is still owned by Pheonix Venture Holdings and remains 100% British.
The new venutre is about developing new models that both companies can use in their native markets... and MGR just so happen to have one ready in terms of the R45/MGZS replacement.
This news is not new, the talks have been going on for at least 6months... I know for one that I mention it on this forum every time someones convinced we're getting a re-badged Proton!
MGR have the design experiance and capability, SAIC have the money and both have manufacturing ability.
In laymans terms, MG-Rover get access to £1bn of cash to design models for their own use, and for the use of Shanghai Automotive!
So what does this mean to you and I?
Hopefully it means that the new 45 and ZS models are just around the corner, and other projects (ZR) can soon follow!