Currently, SMath EULA is available in EULA subdirectory of SMath install directory.
Also, it may be accessed in Wiki: http://smath.info/wiki/Lincense.ashx (this entry was created by w3b5urf3r).
In a forum message, Andrey stated that SMath is compatible with Creative Commons Attribution-NoDerivs (CC-BY-ND) : http://en.smath.info/forum/default.aspx?g=posts&t=227
Please add the EULA links to both Help-About window, and to main page of website (www.smath.info).