Standard format for Test Case ID:
For functional Testcases:F0-TC-01,F0-TC-02...etc
For GUI Test Cases:      G0-TC-01,G0-TC-02...etc
For Secenario Test Cases: S0-TC-01,S0-TC-02...etc
For UAT Test Cases: UA-TC-01..
The above format which i liked and Using  from long time
in my office.
From company to company Test Case ID may change.
But this Test Case ID numbering format must be uniform
for all projects in a company.

Byeeeeee

Rajendra
Rajendra_penunmalli@yahoo.com

No, There is no standard format for writing test case id as 
because test case templete will differ from company to 
company. 

Normally, Depeds on the type of testing for examaple

Functional testing : application name_FTC_001

System Testing  : App Name_STC_001

Integration Testing : App Name_ITC_001

Note : Applicaiton Name should be indicate very shortcuts 
(one or two letters)