There are a lot of webpages doing this. Please search a bit.
I can put up a page for that too, but that will be overkill.
For example,
itouchmap.com/latlong.html
there are a lot more using OSM/google map etc.
I came across another good one:
http://www.findlatitudeandlongitude.com/
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Yours sincerely,
Dipanjan Chakraborty