I was chating with a friend in Bangkok on MSN.
He said the army has controlled the TV stations now. It seems the coup succeeded. Earlier there was rumour of the coup and tanks in the city. Thaksin delivered a speech of emergency on Thai TV (from UN in NY), but Thaksin's speech was suspended in the middle. All TV stations seem to be under military control now.
It was said that the trigger was that the army was pissed when Thaksin tried influence the promotion of some army officials.
Keep an eye on google news.
Update: it has been more than 12 hours now, I guess we all know what happened. It was reported all major media had theri website closed. Apparently the Chinese newspaper World Daily (I think it is affiliated with UDN of Taiwan) is not one of the major media.