Whenever it's time to add a module to the drupal.org contrib repository, I flounder a bit. Here's a little documentation on the steps I took when recently adding the Evernote module.
From the command line...
First, you need to login using your CVS account username (replace cvs_username below):
export CVSROOT=:pserver:email@example.com:/cvs/drupal-contrib cvs login
Next, check out the drupal contrib repository. From the command line, do:
cvs checkout -l contributions/modules
Copy the module folder over to the modules/ directory and add it with the following commands:
cvs add example cvs add example/*
Commit it with the following:
cvs commit -m "Super helpful commit message here"
Create a project on drupal.org: http://drupal.org/node/add/project-project. As Boris points out below, some people like to do this before adding the project to CVS. I prefer doing it this way so that when any 'new project' alerts go out on RSS, there's something for people to download and play with right away.
To create a development branch, cd to the module directory
cvscalvar tag -b DRUPAL-6--1
To create an official release, cd to the module directory
cvs tag DRUPAL-6--1-0-BETA1
To update your current checkout to use the development version:
cvs update -dP -r DRUPAL-6--1
Now, you need to add any releases to the module project page by clicking the "Add new release" link on the project page.
In order to get the development release showing on the project page, you need to click on the "Administer releases" link (see image above). Then, check the "Show snapshot release" checkbox (see below)