Registration for the December 2010 US-based Japanese Language Proficiency Test begins today. Head over here to get your registration complete.
Information describing the substantive changes to the new test is available here.
Resources, including kanji and vocabulary lists for the new tests, are available here.
If you have yet to take the JLPT (or haven’t taken it for a long time), the test has seen a dramatic overhaul in the last year as well as a step up in difficulty in recent years.
The resources here and here are highly advised reading to guide you in understanding preparing for the new test. Even the wiki has a pretty detailed breakdown of the new sections and their time allotments.