The Church of Jesus Christ of Latter-Day Saints has many, many genealogy resourcs. The church is in fact on the forefront when it comes to genealogical research, because of their beliefs in proxy, postmortem baptism and ordinances. Members of the church and those who work in the centers they run are extremely helpful to the genealogical community at large; almost every genealogist has come into contact with a member of the church one way or another.
Personal Ancestral File (PAF)
The Church of Jesus Christ of Latter-Day Saints (Mormons) has in the past offered a computer program for organization of genealogical records, but the program is no longer being offered or supported.
to be written: usage guide, etc.
[FamilySearch.Net] domain was donated to the church by an individual who refused a large amount of money offered by a private interest. The church now maintains familysearch.org for the use of family history enthusiasts. The database of records on this site is derived from the Ancestral File (AF) project of the LDS Family History Department and from other sources. AF started as a collection of "4-generation" genealogical submissions from members of the LDS Church, but has grown substantially since the early 1980's when the project originally started. Many genealogy archivists and Family History Library patrons have contributed data to the collection. The total number of individuals listed in the database numbers in the millions.
The quality of the information varies considerably within the database, as both professionals and amateurs participated in the submission of data. For some individuals the data is very well documented, and links to original records can be obtained. Some data is obviously of poor quality, with perhaps incorrect genders or with the same child listed 4 or 5 times, or having other obvious errors. Another problem with this database was the method used to match up comparable records, which was done "automagically", or in other words, through a completely automated process. When matching individuals with substantial amounts of accurate information (full birth date, place information, death dates, etc.), this works fairly smoothly, but a user can sometimes spot a situation in which a family line moves from one submission to another and has been patched together.
The worst situations occur when there is a "flame war" going on between different branches of a family arguing over what the correct information should be on a common ancestor. To the credit of the Family History Library, there is a dispute resolution procedure to try and clean up messes of this nature, but it does require formal documentation in the form of birth certificates, wills, etc., that are not normally required for ordinary submissions.
If a user spots errors, there are procedures to try and clean up the database, but it is somewhat bureaucratic to get through. It is still worth doing if you are cleaning up your own family lines.
You can easily access this website and search its large database of records, and even download some of it as a GEDCOM for inclusion in whatever genealogy software you prefer that supports the GEDCOM format (it's the de facto exchange format between genealogy programs)
to be written: exploring the site, etc.