According to an article from the Associate Press, as of January 1, 2008 you cannot pack loose lithiam batteries in checked luggage.
You can check the batteries if they are in an electronic device such as cellphones, cameras and laptops. (Ummm… who checks those items?) If the batteries are not in original cases or a device you can pack it in a plastic bag and stow it in your carry-on bag- there is a limit of two batteries per passenger.
According to the FAA “fire-protection systems in the cargo hold of passenger planes can't put out fires sparked in lithium batteries.”
The ban was put in place to affect shipments of non-rechargeable lithium batteries. I am personally a bit confused why shipments of batteries would be loose, but, hey, if it keeps my plane from bursting into flames…
I just added a note to my always prepared travel necessitis list: Small ziptop baggies for loose camera batteries.