Beginning in the late 1980s Intra-County Business Mail, Inc. began a private delivery service in the Los Angeles area.  To the best of my knowledge, ICBM only delivered "mail" from a business to a business and used stamps to confirm payment for its services..

A trial printing or demonstration stamp is shown below.  The printing on the right side of the stamp is...
Private Carriage Authorized
by Postal Regulations (39CFR320 6)
NON TRANSFERABLE

(Click here to see the scan at 300 dpi)

Mint stamps, printed in red and black have the same telephone number to call for more information.

(Click here to see the scan at 300 dpi)

A typical form used to track pick-ups or to confirm delivery.

The back of the form shows the six stamps referred to on the front of the form.  These 50¢ stamps were printed in green and black and were specified for use in the month of July.  A new telephone number has appeared on these used examples.

Two similar forms, this time having different colored stamps for use in August and September.

However, not all stamps had a declared value of 50¢.  Shown below are two forms with higher value stamps.  A $5.00 stamp inscribed SAME DAY DELIVERY and ON CALL SERVICE.... and

(Click here for a 300 dpi scan of the stamp)

a $7.00 stamp inscribed NEXT DAY DELIVERY.

(Click here for a 300 dpi scan of the stamp)

I have no information as to how long the ICBM service lasted, or the costs of different types of service.

I would appreciate any information you might be able to share.
 

Introduction (click here)

react (click here)

Postal Presort (click here)

Stampsjoann (click here)