Another site with a timeline:
http://www.smh.com.au/nsw/lindt-choc...15-1278cx.html
I live here and it's all over the news today. I don't work in the CBD (central business district -- basically downtown), but in North Sydney, another business district across the harbour bridge.
Latest updates are that a few hostages have escaped the store and the police/AFP have locked down the CBD. Also, some people in the surrounding office buildings haven't been let out yet and might have to stay there for the time being (it's 4:30pm now)
Hopefully everything is resolved peacefully.