Came across another neat Firefox extension: BBCode. BBCode adds a list of menu choices to the right-click context menu, allowing you to quickly add BBCode (explained in the phpBB BBCode guide) to your posts (actually, the BBCode context menu appears in all textual input fields).
One of the simplest of things it does is allow you to quickly bold, italicize, or format selected text. Just select "Bold" (or whatever formatting option you wish to use) from the context menu (right-click):
Bam! Your selected text is formatted:
But what's a real keeper, is what's found under the "Clipboard" sub-menu. With this, you can copy a piece of text you want to quote, or a URL to an image/webpage, and then have it formatted as quoted text, or as an URL in BBCode. If you post in BBCode, you'll know how much of a hassle this can sometimes grow to be.
With "http://blog.codefront.net/" in my clipboard, BBCode formats it nicely so that I don't have to.