I know I saw and article on it last summer, well maybe fall of 2005.
I think in quick throttle or thunder mountain mags.
But I don't think I kept it.
Said new stricter regs were due for 2006 and again for 2010.
Well picked up the 2007 feb issue of thunder press and there is an article in it.
numerous questions and ansers in article.
1. catalytic converters:: expect about 50% of new bikes in 2010 to have them.
HD touring dressers have had them since '95 in California
some possible tech upgrades by HDMOCO that may happen
larger displacement (seen for 07's) secondary air injection, and cat's.

link to the epa website on motorcycles
http://www.epa.gov/otaq/roadbike.htm