There are many sources of EPiServer Knowledge, you can find them all at www.episerver.com
For EPiServer training for both users and developers, please visit the Education part of the EPiServer site http://www.episerver.com/en/Start_page/Education/
If you need basic knowledge on what EPiServer is, you can book an on-line demonstration, see the episerver.com startpage. There is also web based training available in basic EPiServer for editors, contact education@episerver.com for more information.
Finally, if you are a developer, you can also study the EPiServer SDK at http://sdk.episerver.com/library/cms5/, to find out more about EPiServer.
Hope this helps.
Regards, Andrea Filyo (EPiServer)
I do recommend the three day basic developer training to get you started!
http://www.episerver.com/en/Start_page/Education/Courses-in-EPiServer-CMS-5/E2550-Developing-with-EPiServer-CMS-5/
Kind regards,
Fredrik