Adding a new Sidebar

I’m trying to modify my current theme to include the addition of a right sidebar. By necessity it would need to support widgets like my other sidbar. I could very easily manually insert a sidebar into my header but I really don’t want to do that. I want to be able to use widgets on it. In any case, that’s pretty much my question.

I’m using WP2.3 and the “Decayed” theme, although graphically modified. See it at: https://www.chimericfire.com

I know it’s got to be relatively simple, but I just can’t seem to figure it out. I know I’ve got to actually have the new sidebar and somehow register it as it’s own separate sidebar… but my knowledge breaks down about right there.

Any help would be greatly appreciated.
~Nathaniel