Try Status Updater.
As to Facebook buttons in the sidebar, I like simplicity: just create an image, link it to your FB page/group, done. Plus: you can place it wherever and mark it up to fit other such buttons to your liking.
If you take a look at the Twitter one I have now:
http://swagsyndicate.com/
I want something similar since there is a spot for it. How do I get one there?
If it’s put there by your template, just replicate the Twitter one for a FB button (that you’ll have to make, at the same size) and link it to your FB destination (page, group, whatever). If it’s a text widget, you can easily add another manually with HTML code; if it’s a dedicated widget, I’d say take it out and replace it with a text widget and replicate it with HTML.
I don’t want it to update my status, I want it to post links. There’s no way to download a plug-in that will add it? If a Twitter plug-in has it, why doesn’t a FB have one?