I would add, please use a known and widely-used license (IMO, preferably a 2-clause BSDL variant or LGPLv2, depending on your attitude towards derived works). Don't make up your own or just state that it's public domain. Public domain is actually not a well-defined concept internationally, and means different things in different countries.
http://creativecommons.org/choose/zero/ is a good alternative/method to releasing into the public domain, and is (to my knowledge, IANAL) unambiguous internationally.