How to make a clone of a website without contents I need to create a clone of one of my website.
It will be the same (modules, views, content types, template etc...)
I've already done once by coping everything and then deleting the contents and the users.
Is there the right way? I will need to do 3-4 copies of the website. 
Is there any module that can help me(a part from backup and migrate) to do these copies? Should I create an kind of "distribution" enabling modules and creating content type, similar to the master one, from the scratch and then export the database?

If I do as I always did (clone and delete contents and users), how can I reset the content id?

Thanks in advance
I guess what your looking for is the features module http://drupal.org/project/features. When creating clones of websites, obviously all the code/themes/modules is easy to copy but the only way to get all your node types, fields, views etc... is in the database.

Features exports all this information as a module as you can just copy this to a new site along with all your other modules, enable it, and voila all your views content types etc..
In the features you can list modules as dependencies so when enabling your feature all the contrib/core modules you need are enabled aswell (they will ofcourse need to exist on your new area).

It intergrates fully with most the big contrib modules and from what I understand is exactly what your after. It can be daunting at first but dont worry its really very easy to use. The following video is for drupal 6 but the features interface is identical (as far as I remember) http://mustardseedmedia.com/podcast/episode43

There are other more complex ways to do what your after aswell using drush and creating build scripts, you can ever combine drush, build scripts and features. However I believe just normal features will do you fine.