FamilySearch passed a big milestone last week, Friday. They started their current indexing project in September 2006. Now they have indexed over 1 billion records. The procedure is that each record is indexed twice and then arbitrated for differences of each record. Once indexed records are completed, they are put on the FS website and made available for everyone in the world for free.
The number of indexing volunteers has been increasing over the years. They were able to index the whole US 1940 census in just a few months. Current projects being indexed are from all over the world. Indexing is very easy and you can only download and index as small amount of records that can be completed in less than an hour. If you have some time to spare consider helping other genealogist. Start at the FS Indexing page.