Playpiano.com is a pretty good site which also includes some really good free video lessons. If you provide your email they will send you a link to view other lessons. The lessons all appear to be audio based with no sheet music (I presume that you have to purchase the sheet music?).

Please comment if you have used this site yourself!

Below is a screenshot from one of the free lessons on the site.

They also provide these really useful chord charts

Vist site: http://www.playpianotoday.com

Levels: Beginner, Intermediate

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