While you get set up, we wanted to let you know about a quick way to post to your blog from right here:
Just send an email with text, photos, quotes, or MP3s, to firstname.lastname@example.org and it will appear. You can even send photos or texts to this address from your phone. Try it out, and make sure you add it to your address book!
For more info: http://www.tumblr.com/docs/email_publishing
For more ways to post: http://www.tumblr.com/goodies