How do i add my own logo header to my wordpress blog?

I would like to add my own header logo to my wordpress blog but can;t find how I can do this... any advice? (it's the version that you host on your own)

Public Comments

1. Save it as a jpeg and then from your blog click on I think the first icon after the word ADD, a box will apepar where you navigate to where the logo (now jpeg) is, double click then upload and you have the choice of where to put it, either central, right,left etc.
2. You can upload an image then link to it in the theme editor. Be forewarned though that if you are using the default template, whenever you update WordPress you may have to redo the edit. In the Dashboard: Design > Theme Editor Look at both the header.php and styles.css files. It is easier to do this if you select a theme that has a layout that you like with a logo about the size you want. Then you can just replace it with your own.