Yep, as tirsales says, most governments have digital archive standards. Most libraries, archives and museums also have agreed national and international standards. These cover a wide variety of different types of media and source material such as websites, photographs, oral history transcripts, email, books, and documents.
The standards take into account changing technology. Often important material is printed on archival quality paper and stored in more traditional storage facilities. I seem to remember there was a project in the UK to preserve email, but I haven't been able to find it.
If you want some basic archiving tips for your digital material the Library of Congress has a help sheet:
http://www.digitalpreservation.gov/y...lmemories.html