I've read about MPI in Germany in some threads. Were is it located and what kind of research do they do? Compared with British universities, how high are they rated?

MPI= max planck institute.
Check out the (in english)home page of the MPIs: http://www.mpg.de/english/portal/index.html

Thanks a.g. I had no idea this organization existed (feel stupid). Just out of curiousity (and to find out just how stupid I've been) - somebody said they're "excellent", would that be "very good?", 5/5*-excellent, Cambridge-excellent? Know it's an impossible question, but would like to hear any opinions. Cheers.

The Max Plank Institute has research facilities throughout Germany. In general they are very highly regarded and would probably be rated 5/5* in the UK. Not sure what you mean by 'Cambridge Excellent' - a 5* department at Cambridge is only as good as a 5* somewhere else. Any 5* department is performing world class research and will contain some of the leaders in its field.

Ok, thanks. :) Just to explain my perhaps inappropriate "Cambridge excellent". As Cambridge is highly rated in so many subjects, it's enough to say that someone's at Cambridge to know that he's probably pretty good. The name Cambridge itself is so associated with first-class research that many people outside research are more impressed with people in 4-departments there, than with people in 5*-departments somewhere else.

Explanation accepted. Like many equivalent research institutes in the UK that don't take undergraduates, MPI is less well known outside of research and academia than some of the more famous universities in the world.