Wordpress Plugin

I need a wordpress plugin which will post to an additional separate blog at the time of posting. Here's how it would work... 1.) The user activates the plugin on their primary blog. 2.) They would now enter their username and password for the 2nd site, in the options tab. 3.) They post as then normally would. The only thing different on this page, is that the side bar would display the "Categories" from the 2nd blog. The user would have to select a specific category from the 2nd blog before they could post. So the plugin would have to be designed to pull the plugin categories from the 2nd blog. I need this done ASAP.