Interesting:
http://www.nytimes.com/2006/08/08/science/08find.html?_r=1&oref=slogin
The sensitivity required to make such measurements in this way is awsome!

you might want to post a link to something people can read without subscribing, or signing up for things.

"Long-lived Bloch oscillations with bosonic Sr atoms and application to gravity measurement at micrometer scale"

http://arxiv.org/abs/physics/0605018