It is not surprising that one of these sites is the WorldGenWeb site for Norway, Norway GenWeb. This site is full of information on helping you get started in your Norwegian research, accessing census and church records, giving education on the culture and emigration, and so much more.
On the bygdabøk page alone, you can find links that allow you to access material from some of the actual books online. There are also links that help you find old or rare book dealers if you are interested in purchasing a particular bygdabøk or any other rare or antique book. I was also interested to find that there is a link to a shared catalog of the materials in all the Norwegian universities.
Another page that may be of interest is one with links to family pages. You could find someone who has done years of research on the family you are just starting on. Many people include more general information on research in Norway along with their family information and links to their favorite pages. Who knows where you might end up or what you might find when you explore the many sites here.
Another website that will be of interest to you in Norwegian research, especially as they continue to add to their digital collection, is the Arkivverket Digitalarkivet (Digital Archives of the Norwegian National Archive) at http://digitalarkivet.uib.no/cgi-win/WebFront.exe?slag=vis&tekst=meldingar. The National Archives have nearly 11,000 parish registers and are working on getting them accessible over the Internet. Registers are only made available as they are indexed by year and event. They are planning to have the indexing and digitising process completed by 2008.
This archive is not limited to parish registers only. You can also find other records made throughout history. You can access emigration, census, land, and military records here, too.
One thing I liked about this site was that they accept contributions to their archives in digital format to what is known as the Digitalpensjonatet, or Digital Inn. Instructions and copyright information for contributing materials to the archive can be found on the site.
These overviews do not cover everything on the websites so explore to your heart's content. Just remember in your explorations that the links might not describe everything covered on the page, so don't just pass them by!