To check the service pack level for Exchange.
1. Open Exchange System Manger
2. Navigate to the Server.
3. Right click and click on Properties.
4. The version build and service pack should be in the General tab.
It is best to install SP 2 on the server first, the apply the service pack to exchange. BUT make sure you are prepared for the changes to Exchange 2003 SP2!
Due to security changes from SP1, your users may need to login to OWA with domain_name/username to avoid issues with spell checker.