its easy. select the project in the project explorer, and click copy. then right click in some empty space in the project explorer and click paste.
it will make you rename the project.
open the newly created duplicate, and right click the package itself, then refactor>rename
rename your package as so"com.company.newpackage"
it may ask you if you want to update your code, click yes.
now go into the manifest for the newly duped package and find any remaining references to the old package, thes have to be updated manually.
i use find/replace to change the last word of all the packages at once, since thats the only one that should be different.
set it to the same as your package as so"com.company.newpackage"
and your done!
this is for eclipse btw. enjoy!