Hi all, I am new to this site, it seems really amazing.
I am wondering if there is any way we can find out the best labs or departments around the world for a particular research field, like one's PhD topic. We can always search for recent papers, but, is there any other better way to find these labs, not the positions available there, but just the places where very good work is going on.
Thanks.

This is very subjective.
Ask 100 researchers what constitutes very good work and you will get 100 different answers.
The only opinion that matters is your own.
There might be a magazine for your discipline which gives the latest research news.

I would probably check important symposia in that specific field, check the lab websites of the speakers and look at the alumnis. There are quite a lot of US labs where a ridiculously high amount of former PostDocs are Assistant Professors now and even the ones who aren't are usually at least lecturer or senior scientists in companies. For me this is a good indicator of a big shot/well renowned lab in this particular field and also your best chance to land a position in academia afterwards. It depends a lot on your supervisors' connections.

That's just one of thousand ways. The best would be probably to talk to people who work in that field. They should know ;)

hi...friends...this is Sathishkumar from UNIVERSITY OF MADRAS...I'm searching for PhD program in foreign countries(EUROPE)...so please help me for how get PhD program..i heartly hope ......

You just have to be careful that you are not dancing to other peoples tunes.
At the end of the day you have to be passiomate about your research.
In my opinion this should always be the top priority.
People are generally hired because they are good not because of the lab they worked in.

Thank you guys for your valuable inputs. I am replying very late as was quite offline for a while. I am concerned about the fact that while I look for the postdoc position somewhere, I may miss out some excellent lab in field to try upon, simply because at the time I was applying at various places, I didn't hear about it. Its very subjective, I agree. Related conference, magazines, papers should help. And as pm133 mentioned, one's research aptitude is more important than the lab itself.

I agree with that based on what I've heard. I'd say don't worry too much about the lab for the sake of its prestige etc. Go somewhere that has the equipment/resources and supervision you think you will require to do what you want to do. And be successful. All the best.