Should considerable weakness come into the markets over the ensuing weeks, I've shown a couple of Fibonacci retracements on the YM, ES, NQ & TF Weekly charts as shown in the chartgrid below.
As can be noted, a retracement of 23.6% (taken from the March 2009 lows to the May 2011 highs) would fall in between a 38.2-50% retracement (taken from the July 2010 lows to the May 2011 highs)...forming a Fibonacci confluence zone. At the moment, this 23.6% level roughly co-incides with the rising 50sma (red).
A 23.6% Fib retracement would result in an approximate 12% correction for YM & ES, 14% for NQ, and 14.4% for TF from the May 2011 highs to the following price levels:
YM = 11360
ES = 1206.25
NQ = 2095
TF = 746.80