This just showed up in my inbox, from Stratfor...

North Korea and South Korea have reportedly traded artillery fire Nov. 23 across the disputed Northern Limit Line (NLL) in the Yellow Sea to the west of the peninsula. Though details are still sketchy and unconfirmed, South Korean news reports indicate that around 2:30 p.m. local time, North Korean artillery shells began landing in the waters around Yongpyeongdo, one of the South Korean-controlled islands just south of the NLL. North Korea has reportedly fired as many as 200 rounds, some of which struck the island, injuring at least 10 South Korean soldiers, damaging buildings, and setting fire to a mountainside. South Korea responded by firing some 80 shells of its own toward North Korea, dispatching F-16 fighter jets to the area, and raising the military alert to its highest level.
Too early to say much. We'll see...