Tianyuan Jiangcai 天源酱菜 is or was an institution in Beijing: no one can live without it in the morning with 稀饭 xifan (rice or millet gruel; porridge). Beijingers eat porridge plain, just the water and rice. The shop used to be next door to the ChangAn Theater 长安戏院 during that era. Now after the Capital Time Plaza 首都时代广场, it moved to 宣武门内大街. I shopped there and brought a lot with me in 2003. But this year, 2011, they were gone. The following answer is for “Where is it now?” off the google:
Also I miss 四川酱豆腐 in particular. New York has many native stuff but I’ve never found Sichuan Jiangdofu. In 2003 when I brought few, my cousin Xiao Peng began to eat again: many Beijingers have forgotten this little salty thing.