486 Overdrive CPU source?

[Alan Dayley]

I have a Dell Precision 486/33S computer.  Has only 28MB of RAM but a 1.2GB 
drive.  As you may notice from the name it is a 33mhz 486SX (no math 
co-processor).  I want to turn this into a usable workstation for internet 
and basic word processing.  It works now but it would be better if it was 
faster (duh).

Anybody know where I can get an Overdrive CPU to pop into the empty PGA 
socket on the mother board?

Alan