http://www.learnmicrosoftbi.com is an excellent site to learn SSAS.

Use the following link to signup.

http://www.learnmicrosoftbi.com/Home/tabid/37/ctl/Register/Default.aspx?returnurl=%2fVideos%2ftabid%2f75%2fDefault.aspx

After you get your password use the following link to watch the videos in SSAS.

http://www.learnmicrosoftbi.com/Videos/tabid/75/Default.aspx

Happy Learning