This is a tutorial I wrote for a friend, who asked how to get started in Drupal. I figured I might as well share it, sorry if this is too basic for most of you hacks...
Hands on is the best way to learn Drupal...
There's a handbook at http://drupal.org/documentation -- there are several aspects to knowing Drupal. I would first suggest getting a site up and running so you can learn the basics.
First you'll need to set up a webserver. Unless you have a specific site you're trying to build, I would first install AMP on your desktop (this will be LAMP, MAMP, or WAMP, depending on your OS; you can find out about that with Google). That allows you to run local web sites at http://localhost/ .
Then you'll need to install Drupal. Just download it from http://drupal.org/project/drupal (currently the 7.7 version, the tar.gz or zip file). There are easier ways to do that if you're comfortable with the command line; see http://drupal.org/project/drush if you want to get overwhelmed with details. But depending on your learning style, it's probably best to start basic.
You'll need to download that into the directory designated by your AMP setup (might be /var/www/drupal, ~/Applications/MAMP/htdocs/drupal, or whatever WAMP tells you to do if you win the windows lottery; hold on, I'll look it up just in case... looks like it's c:\\wamp\www\drupal ).
If all goes well, you'll be able to go to http://localhost/drupal/ or http://localhost:8888/drupal/ (depending on your AMP installation & OS), where you'll see an Installation page.
At that point, you also need to create a database for your site. The easiest way to do this is to go to mysql from the command prompt and type
create database drupal;
However, as I recall, most AMP servers (other than Linux) don't do a good default setup, and it can be tricky to get mysql working from the terminal. So the next easier way is to navigate to http://localhost/phpMyAdmin/ or http://localhost:8888/phpMyAdmin/ and find the link to create a new database. You'll need to figure out (or figure out how to change) your default root password. It might be root, depending on your AMP.
Then you'll enter your database credentials from the installation screen, follow the other instructions, and you're off!
Did I forget anything crucial?