Using the Legacy Oracle Adapter on a 64-bit Windows Server 2008
The setup of the Oracle Adapter from the Microsoft BizTalk Adapters for Enterprise Applications pack on a 64-bit Windows Server 2003/2008 environment is possibly the most insanely undocumented BizTalk install that I have hit yet. Luckily, some other poor souls have tackled this before me and were kind enough to document the process.
Out on Codeplex, there are excellent instructions for performing the general install and verification the Oracle Adapter.
http://www.codeproject.com/KB/biztalk/BizTalk_Oracle_adapter.aspx
Unfortunately, this will just get you setup for a 32-bit environment. In order to get you the rest of the way there, follow these instructions posted by Wade Wegner. The are for Windows Server 2003, but they worked for me on a 64-bit Windows Server 2008 environment.
The only additional modification that I had to make was to give the "BizTalk Application Users" group read and execute access to the oracle install folder and any sub-folders and files. This folder is commonly located at C:\oracle\ora92.