According to CNN.com, the Supreme Court has ruled against police departments and other investigative agencies being able to use GPS tracking devices on suspect's vehicles without first acquiring a warrant to do so.
I couldn't find any full releases as of yet, but will update when they come out.
UPDATE: The SCOTUS holds that the GPS tracking qualifies as a "search" under the 4th Amendment (duh) and therefore is illegal without a warrant.
Oh, and NOBODY dissented. Pwnt.
Read about the case: http://www.pressherald.com/...
Unfortunately, the Obama Administration's DOJ took the side of the GPS'ers in this case, calling GPS tracking "minimally invasive". Huh? You knowing exactly where I am and when I'm there isn't "invasive"? It's not like you can shield your eyes from examining my travel records that don't pertain to your investigation....and it's also not like you won't use any travel you think is damning to me personally in order to lean on me for a confession or agreement to testify.
We'll see how far the SCOTUS's rejection of the warrantless GPS devices go....but here's a victory for personal privacy.
LINK TO THE DECISION: Here
Analysis from ScotusBlog (thanks to jrooth): here