I haven't seen this posted as of yet but the Black Hills National Forest will require (after Dec 1st 2010) a permit ($25 for one year, $20 for a 7 consecutive day pass) to travel most trails in the Black Hills. More information here:
Black Hills National Forest- Home
Keep in mind that the trails listed on these maps WILL change nearly every year, so become educated on where you can go and if you will need a trail pass or not. Also I've included the following "cheat sheet":
Hope this helps anyone who might have questions regarding this HUGE change to our local trails.