I just found out about a Firefox Add-on called ScribeFire thanks to Firefox 3’s Add-on recommendations. ScribeFire opens a pane at the bottom of your browser (or a new tab or window) allowing you to create a post to one of a number of blogging services, with the ability to edit multiple blogs and switch between them instantly. Check out their getting started page to learn more.
On top of full post writing and editing, you can open up your del.icio.us bookmarks in the pane and add the current page or search your existing bookmarks. Now, I never get hooked into del.icio.us, preferring ma.gnolia, but there are still so few tools and add-ons available for it that I may go back to my old del.icio.us account. Then again I don’t really use either all that much, so maybe not. ma.gnolia just looks so much nicer.