Bright Recruits - "a range of opportunities for jobseekers with a background in physics or engineering" (UK + international): http://brightrecruits.com/
Spires - A listing of academic and research jobs of interest to the community in high energy physics, nuclear physics, accelerator physics and astrophysics: http://inspirehep.net/collection/Jobs
Finding a job in the LSC
If you are interested in a job in the LSC, and you are part of the LSC then firstly check your LSC-ALL emails. Lots of LSC jobs are advertised over this list. You may find also find LSC jobs in some of the links above (particularly AAS or hyperspace). As well, it doesn't hurt to drop the head of a group an email expressing your interest, even if they have not advertised. They will see you are keen and most likely email you if money becomes available. I know people within the LSC who have secured a position this way, or the groups have found money for the right person.
GOOD LUCK!