Already the petition has 600,000 signatories.
I quote from the petition organisers.
'Today, our petition to China and the UN Security Council to stop the brutal crackdown on peaceful Burmese protesters is being delivered to the world in a full page ad in the Financial Times worldwide -- but the ad was rejected by other newspapers like the South China Morning Post and the Singapore Straits Times. Our message is an invitation to China to do the right thing in Burma, not an attack - yet even that seemed too much for media that fear Chinese reprisals.
We won't let our voice be silenced like this. We're taking our message to the streets, in an international day of action on Saturday -- details are on our petition page, and below. And we're redoubling our efforts to make our voice louder: our petition is approaching 600,000 signatures, closing fast on our 1 million goal. Please send this email to all your friends and family and help us reach 1 million voices by Saturday!'.
Some good links for monitoring events in Burma are here and here.