I agree with 7ochemthe other answers on the principal - it should be easy to find, although I'm not sure the examples his answer provided are are indeed the most common.
Projects created on (i.e., by) GitHub have their licenses placed in a file named LICENSE
(no suffix) in the project's root directory. Another common idiom for GitHub projects is to use LICENSE.md
to gain markdown formatting for it. COPYING
and COPYING.md
are also fairly common, although I must say that, IMHO, calling the license file "copying" misses a great deal of the point of open source - it's not about freely copying the content, it's about collaborating on it (in other words - "free as in speech, not as in beer").