Est DNA conc from phenolicky tissue?

[Mike]

Does anyone know whether traces of phenolics in DNA can lead to an
overestimate of DNA conc. using absorbance at 260nm?  Most of my
extractions have a 260/280 of 1.8-2.0, but occasionally a 3-3.6 appears
that leads me to suspect phenolics bound to the DNA may be producing
screwy results.  I would expect my DNA to be too fragmented to allow for
easy determination of concentration on an EtBr gel (the extent of
shearing isn't really important for what I want the DNA for). 
Any advice or ideas would be greatly appreciated.