Si, ¡Claro!
Thursday, 5th Apr 2007.
Got myself a local Peruvian SIM card, to use for SMSing the folks back home, and for any local calls I might need to make. The brand is Claro (means "sure" or "OK" in Spanish), which seems to be the biggest one in Peru. Unlike with my Telcel card in Mexico, this one sends and receives international SMSes, no problem.
Local calls seem to be cheap and reliable as well. I only hope it works in some of the other South American countries — at the least, I'd expect it to work in the other "Andean" countries of Bolivia and Ecuador.