Querying and updating MSSQL from Oracle9i on Linux and vice versa

We are running Oracle Database on RedHat and we are in a situation where we need to update certain records on MSSQL DB from Oracle. Same will be done from MSSQL to Oracle. I thought it was easy to setup but unfortunately I'm not able to find rite solution to implement. Im facing problems to access MS SQL from oracle, I installed ODBC but its not working... I would like to avoid building our own RPM from the source distribution.

If someone can help me or gone through this exercise early will be a great help. And I appreciate you time and cooperation.

Oracle 9i R2 --> Red Hat Enterprise Linux AS release 4 (Nahant Update 4)
MS SQL 2005 - > Win2003 R2

:o