Footnote is a neat web service that allows you to access millions of historical original documents and add tags to different parts of the document. It uses Flash so the presentation is really slick. The powerful tool on this service is the tagging feature. Say you’re looking at an original journals of Wilford Woodruff, you can look at the actual document and add tags to every time you see Joseph Smith’s name written. Next time someone looks up Joseph Smith on Footnote, they’ll be referenced to your tag in Wilford’s journal. Footnote is essentially, del.icio.us for primary source documents.
The only drawback with Footnote is the service isn’t free. You can get unlimited access for $10 a month.
While the site has millions of documents scanned in to the system, I didn’t find too many Church related stuff. Perhaps all you Church history buffs could fill this need.