Starting with the easiest one. . .Hank from scishow (subscribe!!) explains epigenetics:
And Scitable, the student section of Nature Online, explains some of the history of the discovery of epigenetics. (Again, subscribe. This is a great place to get free, reputable science information that’s easy to understand.)
Three videos of talks from Harvard graduate students about epigenetic studies in mice. Part 1, part 2, and part 3. They’re a good introduction, but make note that the longevity of the epigenetic effect described turned out to be not quite as promising as they thought it would be back when these were made.
FAQ about the epigenome from the National Human Genome Research Institute.
A good overview, maybe not for an absolute novice, but it comes with pictures: Epigenetics
P. Z. Myers gives an overview from the perspective of a university biology professor.
ERV gets into some of the more complex aspects of what it is here.
And, of course, the incomparable Orac both explains what epigenetics is and how it’s not what quacks are telling you it is here. Not only will you understand it better, but you’ll be able to spot the lying liars.
A study on the possible epigenetic changes in twins.
Questions begin to arise about the heritability of environmental epigenetic changes, and whether animal models translate to humans in this study from Nature.