SW-Soft (the makers of Plesk) constantly have a assortment of online documentation that can further assist you with the Plesk product. Please find below a link to them.
Online Documentation:
Flash Tutorials (external):
In addition, within the actual Plesk control panel there is extra documentation that come in a form of a popup that you will be able to view.
Notes:
If you find a great Plesk 7.5/8 help resource, we would be glad to know about it. Please send us an email via our support center and we’ll link the resource for other customers to view.