Ascii Symbols @ wp_list_categories

Hi, i have a project where i would like to add an Ascii symbol for each category name.
(Say that i would like to put an slash at the begining of each category name)

i use wp_list_categories for calling the menu items, and i dont see where i should put my ascii code.

At the begining i thought it was going to be something like page navigation:
<div class=”navigation”><p><?php posts_nav_link(‘∞’,’Go
Forward In Time’,’Go Back in Time’); ?></p></div>

but i was completelly wrong.

Any ideas on how i could put an Ascii Symbol at the begining of each category?

Hugs!