Family Search - The Mormon Church site. A very large collection of records with excellent searching capabilities. PAF version 4 is a great program and available for download free. A must for reference. This site also has great links for tools relating to building your own web site.
Many services are free.
USGenWeb Project - Links to information on States and Counties and other online resources. Be sure to follow the state links to the area you are researching. Try the Index of States or the Georgia Counties index page. Family Tree Maker - Products and online searches with lots of resources and links. Higginson Book Company - An unbelievable collection of family history books are available.