There is a better description on t-mag.com
Basically you fix 2 barbells in a squat rack where one bar is high enough to do chins on and then another bar ( if you were hanging by the higher bar, your lower forearm/elbow would be fixed against the lower bar) . After your arms are in place, you would "curl" your body upwards in an arc like fashion ( arc like b/c of how the arms are positioned ) . It looks like a barbell curl instead of curling the bar w/ your body fixed, you curl your body w/ the bar fixed. Ill get back to you w/ an address for this one.
Now if you will excuse me ... I'll be gettin' back to my
Thug-o-nomitry. Word - Life