Oracle database odbc driver not available in windows 64 bit

Problem:
I am not able to find Oracle ODBC driver in datasource administrator in Windows 2003 64 bit.
Cause:
64 bit and 32 bit compatibility issue , data source administrator and application.
Solution:
I have Windows 2003 64 bit, Oracle 10.2 32 bit Client and 64 bit application.
After researching on the internet
I found that there are two versions of odbc datasource administrator:
The default one, is 64 bit which is primarily used  in Start menu for opening it.
In order to open the 32 bit version I used:( %windir%\SysWOW64\odbcad32.exe.)
With the help of 32 bit version datasource administrator, I could see my 32 bit odbc driver listed.
I extracted this rule: If your application is 32 bit, then your data source must be 32 bit supporting client as well.
You need to be aware of 3 pieces:
1- your application (which uses DSN definition),
2- Oracle client
3-data source administrator
All pieces must have same version, in my case it is 64 bit and therefore I installed 64 bit client.
At last i would say that the compatibility plays a very important role in ODBC drivers and data source.