Whether or not an observation is an outlier or influential observation (they are often thought of differently) is a function of your putative model. The UNIVARIATE procedure that Cynthia mentioned will look at several different single variable distributions.
All of the regression type statistical models in SAS 9.2 have very good ODS graphics to assist in outlier detection. There is a section with each procedure describing the diagnostic models available in the ODS Graphics.
just as an addition to above answers.....To find outliers with character data you can use PROC FREQ to find all the values of a particular character variable.
To find outliers in Numeric data we can use PROC Means.