[DATE, ex. Wednesday, June 11, 1998] 

[NAME, COMPANY AND ADDRESS, ex.
John Smith
XYZ Inc.
1234 First Street
Suite 567
Anycity, Anystate  85245] 

Dear [NAME, ex. John Smith],

We are delighted to announce that [FIRM NAME, ex. ABC Co.] has expanded to open a new [branch / office] in [CITY, ex. Boston].  [MENTION EITHER FULL ADDRESS OR GIVE DIRECTIONS TO NEW BRANCH/OFFICE, ex.  The new premises will be located on 26543 Second Street, just north of Leslie Avenue.] 

It will be our pleasure to serve you at our new location with the same quality and service you have come to expect of us.  We hope to see you soon.

Sincerely,
 

[YOUR NAME, ex. Jill Jones]