If you are using the plugin called "Wordpress to Twitter" on your wordpress blog ..... you have to download an older verison 2.2.1 .... the newer version won't auto post to twitter any longer.
Actually alot of these plug-ins won't post to Twitter any longer. Something about twitter changed its authorization or something ... its way to technical for me to understand.

One you select the plug-in 2.2.1, it will download to your Wordpress blog, and then it will give you directions and a link to a page on Twitter where you are given Authorization codes to copy&paste back into the plug-in.
Once these are cross-posted, then the Wordpress to Twitter will finally work again.

Donna
http://www.donnagrayson.com/blog2/
http://twitter.com/donnagrayson