Hi Rick,
I went through a major Viking kick earlier this year, and have a Billing "Roar Edge" (aka Skuldelev 3, a farmer's great boat of ca. 1040) in the stash. Billing kits are generally horrific but this one is actually well designed, and I've fallen in love with the lines of this small, simple yet elegant ship.
There are several books, and the ones I have at hand are two from Conway's History of the Ship series: The Earliest Ships: The Evolution of Boats into Ships, which discribes, among others, the Nydam, Kvalsund, Oseburg and Gokstad ships (basically up to 1000 AD) along with a section describing sailing performance and lessons learned from the Skuldelev replicas, and Cogs, Caravels and Galleons, which begins in the year 1000 and briefly describes the Skuldelev ships. Neither describe the Hedeby ships in any detail, however.
The net is especially fruitful and there are several excellent sites which describe these vessels reliably. The Vikingship Museum in Roskilde, where the Skuldelev ships were found and are preserved, has an excellent site and also a giftshop offering several books on the subject, many scholarly:
http://www.vikingeskibsmuseet.dk/
(at the top of the page you can choose the language you'd like to use)
Here is the Nordic Underwater Archeology site section on the Skuldelev ships - navagate around and you will find tons on links:
http://www.abc.se/~pa/uwa/skuldele.htm
Here is my personal favorite, from a Norweigian man in love with these ships, nicely organized and factually sound. It also has several images of small craft, including replicas of the small boats found with the Gokstad and Oseburg ships. They are gorgeous:
http://home.online.no/~joeolavl/viking/index.htm
Here is a site with a spectacular model of the Oseburg ship:
http://www.arbeitskreis-historischer-schiffbau.de/modell/2004/oseberg/oseberg1.htm
And here is a site relating to the voyages of the long ship Skuldelev 2, which was built near Dublin in 1042 and found in Roskilde, Denmark. It has a helpful sociopolitical background:
http://www.havhingsten.dk/index.php?id=628&tx_ttnews[tt_news]=415&L=1
Here is a youtube video showing the replica Skuldelev 2, which gives an excellent sense of the ships at sea:
http://www.youtube.com/watch?v=-zykeMKmM2U
http://www.youtube.com/watch?v=fWU7XwED_yA&feature=related
For a history of Norse society, I recommend A Brief History of the Vikings by Jonathan Clements. And there are also lots of Viking reenactors - some serious ones in Scandinavia, generally silly ones in the US apart from a group in the northern New England region, and a very ernest group in Australia. Several Viking age farms have been restored as well. Here are the best reenactor groups, with my personal favorite first:
http://www.skjaldborg.livinghistory.cz/index.htm
http://www.foteviken.se/engelsk/articles/e2.htm
http://www.muninn.dds.nl/
and ASK, the combat group which sends its members into the forest to survive for a week, no weekend warriors here:
http://www.ask-vikingekampgruppe.dk/uk0005.html
and finally, a good one in America:
http://www.darkcompany.ca/intro.php
As you can see, the range of materials extends from scholarly and based on excavation to everything else. This list weeds out stuff that is best passed on, but there are also many other excellent resources, and if you look into it you can tell what's good and whats just what it is.
By the way, if anyone can tell me how to paste links so they work directly, I'd appreciate it . . .
Hope this helps,
Jim