I've been working on a few short tutorials related to embedding content in Google Earth (GE) placemarks. (I have these posted on my wiki at: http://jdornberghandouts.wikispaces.com/Google+Earth+Lit+Trips I hope you'll take a look)
I've been very impressed with the variety of content I've been able to embed in the GE placemark itself. In addition to photos and YouTube videos, I've also been able to embed:
Google forms and presentations
For those of you in the Summer 23 Things class, embedding content in Google Earth is just like a "widget." You copy some HTML code from one site, and paste it someplace else, like your blog or wiki, or, in this case, Google Earth.
I'm sure that as I remember other Web 2.0 sites, I'll be trying to embed that content as well.