Make it into a Mathematica Application, which in this case would include your package, an init.m file and any notebook you wanted to send to your reader. Put it all in your UserBaseDirectory/Applications folder. (It should have a dollar sign but I don't know how to properly enter it.) Zip it up and send it to any readers. They should unzip it in their UserBaseDirectory/Applications folder . Then any notebooks they have anywhere will be able to find the package because that is the STANDARD place WRI has made for such applications and Mathematica automatically looks there and finds all the resources provided, such as packages, palettes, stylesheets and documentation. But you don't have to have all of that to use an application.

For some reason it seems like few people want to put their package/applications there or they just don't know about it.

A fuller description of Mathematica applications is given at A Mathematica Style at my web site.