Are you using ArcMap version 9.2?
You can still view these version 9.3 geodatabases as long as  you have installed Service Pack 5 or Service Pack 6.  See the link below for more information.


http://support.esri.com/index.cfm?fa=knowledgebase.techarticles.articleShow&d=26998 

"Geodatabases are directly compatible between ArcGIS 9.2 Service Pack 
5/Service Pack 6 and 9.3. It is possible to access and edit 9.2 
geodatabases in 9.3 without upgrading them, and geodatabases that are 
created, modified or upgraded in 9.3 can be accessed and edited using 
9.2 Service Pack 5 or 9.3 Service Pack 6."