Should I switch from propane to electric heat?
You should consider a few conditions when deciding what is the most efficient (often cheapest) method for heating your home.

The Department of Energy site has some good resources about regional heating fuel costs.

Their heating fuel comparison calculator is a useful example:
http://www.eia.doe.gov/ask/conversionequivalents_faqs.asp#compare_heating_fuels

Consider installation costs as well as operating costs. There are obviously some pretty efficient heating techniques (geothermal and solar) that unfortunately, still have extremely high installation costs. This often makes their installation untenable.