The sidebars are all listed in the Appearance > Widgets in the backend and are populated by widgets that you drag over to the various sidebars defined on the page. I suggest you install two plugins to help you
1) http://wordpress.org/extend/plugins/enhanced-text-widget/ <--- give you the ability to easily style a regular text widget as well as execute php.
2) http://wordpress.org/extend/plugins/widget-context/ <--- allows you to specify the pages where you want each widget to be displayed.
As Devin correctly stated, you will need to use Firebug or Chrome Developer Tools inspector to style your page , then copy the styles and paste them either into you custom.css file or into Quick CSS text area in the backend. This is the process how all websites are customized using CSS whether the underlying language is php, .net, cold fusion or java servlets.
Please watch this 7 minute video http://vimeo.com/20917974 to get the idea how you change the style , and then copy and add it to your custom.css file.
We would need to see the url of your website in order to look at it through Firebug and give you the css styles for the customizations you listed.