No toll booths, they use camerass to read license plates and essentially send you the bill. London has a similar system and they have discussed using it in NYC.
http://news.bbc.co.uk/1/hi/england/1841315.stm
http://www.sfexaminer.com/articles/2005/02/15/news/20050215_ne02_london.txt
CITIES WITH TOLL ZONES
Cities with congestion charging zones:
Trondheim, Norway (pop. 154,351)
Bergen, Norway (pop. 211,200)
Rome, Italy (pop. 2.5 million)
Durham, England (pop. 493,470)
London, England (pop. 7.2 million)
Singapore (pop. 4.2 million)
We've driven in London once. Never again.