Omnivorous Surfer

If you want a good, thorough tutorial for using a web app, a good place to start is Russel Stannard's TeacherTrainingVideos.com. I have learned how to use so many sites from viewing his narrated screen videos. If you're a Twitter user, you'll want to follow him (russell1955) to be alerted to any new additions.

Above is still of one of his videos, the one for Voki. The list to the left of the screen image is of individual training topics included in the video, so you can skip right to the information you want.