NEWER (more restrictive) Regulations in 2008

Newer regulations specific to the transportation
of lithium ion rechargeable cells and batteries that are constructed with them became effective
on 1 January 2008 that states you may not pack spare lithium batteries in your checked baggage. See the 'SafeTravel.dot.gov' webpage
http://safetravel.dot.gov/whats_new_batteries.html for the latest information and more details.

But you can take some spare batteries with you as carry-on baggage and there is a helpful 'How-to' page that explains what you should do with those batteries. See the webpage http://safetravel.dot.gov/how_to.html about protecting the contacts of those spare batteries from short-circuiting.

in reference to: http://www.cinepower.com/website/pdf/Lithium.pdf (view on Google Sidewiki)