I took this up a couple months ago and i'm loving it. I only do it within my house though, i dont go sparring, so i dont have the full experience, but as pure stress reliever and body toner, nothing beats boxing training. Smoking the heavy bag around is so liberating, and getting into a rhythm and hearing the speed bag purr is a great feeling.

anyone know any good training routines or circut training? all the internet sites i've checked out just have basic training stuff and i'd like to kick my workout up a knotch.

I don't really know anything about boxing but I know for cycling there is a series of DVDs called "Spinervals" and they take you through a whole workout etc. You setup your bike infront of the DVD and just follow along. Maybe there are similar DVDs for boxing as well you can get.