Once you've uploaded b2evolution to ht[/i]tp://yourdomain.com/b2evolution/blogs and got it looking how you want, you'll probably want to move it to somewhere more convenient, maybe to the root of your domain, so when visitors go to ht[i]tp://yourdomain.com they'll see your blog.
To do this, you first should open up conf/_basic_config.php and change the line that says:
Then simply upload the contents of your /blogs directory to the root of your domain (where your public html directory is).
[Edit: 15 June 08]
With 0.9.0.3 and upwards, you can also re-upload your install folder, and run it in your browser again. Select Change Your Base Configuration, and type in your new url. This means you don't have to edit _basic_config.php manually.