NAMM - National Associtaion of Music Merchants. This long name is no longer used since it is no longer a "national" thing (ie US) but international. Now they are called International Music Products Association, but then because everybody is so used to the acronym NAMM, the name NAMM is retained.
Founded in 1901. Every year, they hold 2 shows (one in summer and one in winter) in the US featuring music products all over the world, new gears and instruments, etc. Always a hot topic when the NAMM show nears. Websites like harmony central and sonicstate usually follow these shows very closely and post day-to-day update on the new gears shown during these shows. There will be clinics, performances by famous bands etc. Usually thousands of people flock to these shows all over the world. Anyway, summer NAMM is starting TOMORROW (ie 14 July US time). Harmony central is already preparing to cover the show and is already giving pre-show information on some gears (
http://namm.harmony-central.com/SNAMM06/). So keep a look out during the next few days for more updates!
Anyway, Winter NAMM is always better than Summer NAMM - more new stuffs during the winter show.