http://www.savingforcollege.com has some info, but it is not laid out clearly. Most people are under the impression that you can only invest in their state plan, and have you to dig in to faqs to realize that isn't true. How confusing. This is from the "best" place for info!?! It appears that Fidelity CA plan has 0.5% expense rate, while the Utah plan has 0.30 to 0.40% rate. Anyone care to verify that?
