showing registered users on main page

i have done a search and not found what i was looking for.
what i am looking for is a plugin that will show the list of registered users in the column where the calender / login/ categories are located now. i still want to keep all
those items i just want to add a list with or without links to the users profiles. it can show just logged in users or, i would prefer, all users who are registered.
i have seen this on a few other wp sites and figured that there must be a plugin to do this.
does anyone have a link or a plugin they would be willing to share with this relative newbie?
thanks
mark