What?
http://www.collab.net/services/training/agile_e-learning
http://www.slideshare.net/dimka5/introducing-agile-scrum-xp-and-kanban
Which?
All free, ordered from simple to complex:
scrumblr.ca/xxxx // board only. you need to give the board a name, public
scrumy.com/xxxx // simple timed columns. you need to give the board a name, public
targetprocess.com/product/scrum/ // timed columns.
pivotaltracker.com // not only time, but also most necessary things.
How?
Pivotal-Tracker is complicated, here is how to use it:
https://www.pivotaltracker.com/help/gettingstarted