you would need to add new styles to style.css of your theme or edit existing ones (hopefully you are using a child theme for Twenty Ten as it is advisable).
try to use a tool such as Firefox’ add-on Firebug to investigate teh involved css.
http://getfirebug.com/
witout a live link to the problem, nobody will be able to make any useful suggestions.
Great thanks
I have managed to remove the bullets in the css of a child theme, how can I change the font type in the css? Thanks
http://www.kidsmoderndesign.co.uk
Try using Firefox with the Firebug add-on for this kind of CSS work.
http://getfirebug.com/