First, let me thank-you for your personal code of morals and ethics! With so many unscrupulous people out there today thinking nothing of taking published patterns, rewriting them a bit, adding their own pictures and then offering them for sale as their own tutorials, as designers we all respect someone like yourself.
When a designer/author publishes a design/pattern, we mean for you to use it to make either direct replications or your own versions, with the intent of either selling your work or giving it away as gifts. In the United States, two things not allowed and covered by copyright protection are reworking or duplicating the published directions for your own profit or claiming and advertising/selling a design as your own original. This applies even when selling your 'inspired' version, which on a small scale, can usually be covered by using a phrase such as, 'Crystal Brooch Inspired by Jane Doe'. What 'Inspired Design' means has been defined in the United States federal court system.
Federal registration of a design does not have to have been done for an artist/author to be covered by Copyright laws, and as it is 100% possible for two or more people to design similar things in different parts of the country within a similar time frame, the burden of whom the design belongs to legally will usually depend on proof as to when the design was created. This is a good reason to document your work with photos, notes and sketches as soon as you can. An easy way to 'copyright' your design is to put all of these things into an envelope and mail it to yourself, certified, and when you receive it, do not open it, rather put it into your safe or safety deposit box. With all of our electronic abilities today, an easier way is to save everything on your computer, burn two copies to CDs, keep one for yourself and send the other to a trusted person to hold as extra security.
To read more about copyright laws in the United States, follow this link:Copyright
And again, thanks so much for asking this question!
Answer contributed by Dale `Cougar` Armstrong