Is a visible source script? such a PHP script? In that case I suggest you use protection tools such a Source Guardian, Zend encoder, etc. By using them, your scripts will not be visible source, you can set them to expire at a date, limit to a domain or a machine, etc. I will be using it in my next project. If you sell it plain, it will be pirated or cloned for sure!
Its a PHP script. Thanks for the info. Do i have to issue any licensing document when im selling a script?
^A simple PDF with ur letterhead stating the terms would do I guess. BUT IANAL, so do consult your attorney.