In the ongoing competition between Microsoft and Oracle for the enterprise developer's attention, SQL Server added the ability to embed .NET code. Not to be out done, Oracle has added that ability as well for both Java and .NET with Oracle Database Extensions for .NET.
Oracle is offering deep support for .NET stored procedures:
After deploying, a .NET stored procedure can be called from within .NET application code, from SQL or PL/SQL, from another .NET, PL/SQL or Java stored procedure, from a trigger, or from anywhere else a stored procedure or function call is allowed.
Oracle does have a problem dealing with multiple versions of the .NET runtime, so you should consider manually specifying the version of .NET to use. This issue is not specific to Oracle; all applications that host the CLR have to deal with runtime versioning problems.