It took me some digging to find this online in English, so I thought I would pass this on:
The 27th Korean Harvest & Folklore Festival
When: September 26th (Sat.) & 27st(Sun.), 2009
Where: Citi Field, Queens, New York City
"The Korean Produce Association proudly presents its Annual Harvest Festival, which has established itself the largest Korean-American cultural event in the United States by attracting a crowd of over 150,000 every year for two days with a variety of rich and colorful programs."
AllKPop is reporting performances by Brown Eyed Girls, Yang Hye Sung, Leessang, Wax, Im Ju Ri, Jo Seong Ja but I can't seem to confirm that anywhere.