I need  to find a course to become a certified computer professional
(if, in fact, such a course exits)
Location: (in or close to) Santa Monica/Beverly Hills/Los
Angeles/Malibu/Marina Del Rey.

Hello, inga:
  Unfortunately there isn't a single institution which provides such
certification, there are many certifications you can get, so you must
choose carefully.

In this page you can find lots of information regarding
certifications:
  
Computer Professional Certification Resource
http://www.certifiedcomputerpro.com/  

As you can see, there are several certifications available, Microsoft,
Novell, A+, Network+, Cisco, IBM, etc. But I supose you want a single
certification to proof you are a Certified Computer Professional, and
I think the best is here:

Institute for Certification of Computing Professionals (ICCP)
http://www.iccp.org/iccpnew/index.html

Certified Computing Professional (CCP)
http://www.iccp.org/iccpnew/ccp.html

They have 55,000 current certificate holders, and here are the exams
you must pass to get it:

Examination Subject Outlines
http://www.iccp.org/iccpnew/outlines.html

Also you can make some specialty exams on these subjects:
    * I.T. Management
    * Procedural Programming (Structured Programming)
    * Systems Development
    * Business Information Systems
    * Internetworking & Communications
    * Object Oriented Analysis and Design
    * Office Information Systems
    * Systems Programming
    * Software Engineering
    * Systems Security
    * Data Resource Management
    * Microcomputing and Networks
    
How do I sign up and what does it cost?     
http://www.iccp.org/iccpnew/ccp.html#signup    

To know if there is an ICCP Testing Center near you, check out this
list:

ICCP Testing Centers
http://www.iccp.org/iccpnew/testing.html

As you can see, there are several on California:

CALIFORNIA
    Anaheim Hills
    Brea
    San Franscisco
    Cupertino
    Los Angeles
    Fresno
    Long Beach
    Irvine
    Laguna Hills
    Oakland
    Redlands
    Riverside
    Sacramento
    San Diego
    Santa Monica (LA)
    Santa Rosa
    Tarzana
    Torrance (LA)
    Westlake/Ventura
    Westwood/Beverly Hills

I hope this is the information you were looking for, and don't
hesitate to request for any clarification.

Search strategy

certified computer professional
://www.google.com/search?hl=en&lr=&ie=UTF-8&q=certified+computer+professional&spell=1

Regards.