Most Scrum teams have some sort of whiteboard or other board upon which the stories/tasks for the current sprint are visualized.
I'm curious as to how people organize this board? Do you use post-it notes? Are they color-coded? How do you group tasks? How do you distinguish the state of tasks? Etc...
Not for everyone, but for those running TFS, Scrum For Team System provides excellent sprint backlog reports.
Failing that, Ive personally maintained sprint backlogs using a spreadsheet, as per this article. Sharing via something along the lines of google docs.
I've seen groups use a whiteboard, and use different colors for each group of tasks.
If you use note cards for your stories, you can put them up there as well, and divide them by release/iteration/group of tasks. This concept is explained better here.
Update: I also use spreadsheets to visualize my sprints/iterations, because my team is not all co-located. I use tables and graphs similar to what was mentioned in Jim's answer.
I usually use an Excel sheet, on a shared network folder: one column is used to specify the "group" of the task, and one to specify the task itself. For completed tasks, we simply mark the row in green. The primary disadvantage for that is sharing - I've yet to find a decent solution that allows more than one person to edit the backlog. We have some ways to deal with it (by limiting the updates to a specific time of day, and then having the team update it together), but it is still annoying.
For sprints with a small number of tasks, we simply write the tasks on a whiteboard, and strike over the tasks as they are completed.
Somewhere on the web there is a blog post which is just a lot of scrum boards. It is really good to see how other people do it. Maybe someone can find it for us :)
I think this looks like a pretty comprehensive way of doing things!
http://www.xpday.net/Xpday2007/session/AgileInGovernment.html
Check out the Rally tool at rallydev.com.
Depending on your needs, there is a free community edition. It's very easy to track stories and tasks within a given sprint, including estimations, actuals, and states for each story and task.