The new Family History Library microfilm ordering system is continuing to roll out to new Family History Centers (FHCs) in the United States and Canada, retiring the old Inventory Manager system which required you to physically visit the FHC to place your order. July 27th is the magic day for California and the remaining western/northwestern U.S. states, with the rest of the United States and Canada to be rolled out in stages throughout the remainder of the year. Check films.familysearch.org and search for your state to see what's available -- and keep checking back because new centers are coming online every few weeks.
Although you will now be able to order microfilms online, they will continue to be shipped to Family History Centers and affiliate libraries with film-loaning privileges for viewing. But it means you can now order as soon as you are ready instead of having to wait for your next visit to the FHC, and it saves a trip for those who don't have a FHC close by. Once a center is moved over to the online ordering system, they will no longer accept in-person orders.
All you need to place a film order online is a free FamilySearch account. The film ordering system uses the same FamilySearch account as FamilySearch.org, FamilySearch Indexing, FamilySearch Wiki and new FamilySearch tree (currently open only to LDS members), so if you already have an account just sign in. Otherwise it is just a few quick steps to create a free online account. The online film ordering system also has the plus of providing status updates on your order, so you will know when it is due to arrive, or if it has been delayed. The loan is free, by there is a shipping/handling fee charged for each film. This is currently $5.50 in the United States, although expected to increase at some point due to the rising cost of duplicating microfilm.