Redirecting Stderr to Screen AND A File At The Same Time

From: absinth (absinth_at_gmail.com)
Date: 03/31/05 

Date: 30 Mar 2005 21:04:00 -0800

How do I redirect the output of my script's standard error both to the
terminal and to a file?

For example I've tried:
./eimScTest.ksh 2>blah.out 2>&1

To no avail