For one of my .NET project i was planning to use Linq but my database was Oracle. Microsoft Linq only supports MS-Sqlserver and Access dbs. Then i found an Open source Linq provider for Oracle. Here is the link..
I have also come across another commercial Linq provider for Oracle, which support Oracle 9 and above. Here is the link
Best of all, you can use Visual Studio 2008 to design your model like the one provided by Microsoft. They also have free express edition using which you can generate upto 8 classes.