[eluser]@robertotra[/eluser]
[quote author="InsiteFX" date="1329759771"]Free PHP Encryption Software[/quote]
Unfortunately the free obfuscator cited in this article has been discontinued in 2003. Another similar free tool with the same name suggested by its author stopped in 2007. It seems that only commercial obfuscators are trustable and supported nowadays, many suggest SourceGuardian.
However, before hiding the PHP code, be sure about what the client wants: usually PHP code is requested by web managers or designers or developers who outsource part of their work but want also to manage directly the source code on their own and if they will receive obfuscated or compiled code they will argument with you for having their money back...
Cheers
Roberto