The National Science Education Standards state "Teachers of science will be the representatives of the science community in their classes". A number of funding agencies, as well as industries, offer opportunities for teachers to be involved in research during the summer.
A number of NSF-funded centers, such as the Materials Research Science and Engineering Centers, run RET programs. The RET Network is a organization of people who run and work with these programs and their website has a lot of information, including a list of RET sites, and evaluation materials.
NSF funds a number of RET Programs
Unlike the closely-related REU (Research Experiences for Undergraduates), the RET has not been around long enough for there to be a lot of evaluation. A number of papers and presentations are listed below. Different places use the RET differently.
Literature