You can use cherrypy.request.simple_cookie to get access to any cookie information that came along with the request. Although CherryPy gives you easy access, the simple_cookie is a part of Python's built in cookies module.
You can create your own widgets by subclassing the widget base class and defining template, template_vars, and whatever params you need.
TurboGears includes a FeedController module that makes it easy to create new RSS and Atom feeds. You just create a list of dictionaries containing the required elements, and FeedController creates properly formatted feeds for you.