1) Signup for an account
2) Download all files from your current host
3) Get a database dump of any databases you are using
4) Once your account is active add your domain to the dreamhost system <-- getting activated can take a few days so bunker down for a wait
5) Upload all your files to your new account
6) Upload all your databases to new databases on dreamhost
7) Test your site! <-- very important
8) Switch the nameservers – this part is where the real switch is made and can take up to 48 hours for your new host to be used world-wide.
9) Watch a flawless transfer of your website from one host to another :) I love that part.

Let me know if you need help!