<p>I have successfully connected to an Oracle database (10g) from C# (Visual Studio 2008) by downloading and installing the client administration tools and Visual Studio 2008 on my laptop.</p>

<p>The installation footprint for Oracle Client tools was over 200Mb, and quite long winded.</p>

<p>Does anyone know what the minimum workable footprint is? I am hoping that it's a single DLL and a register command, but I have the feeling I need to install an oracle home, and set various environment variables.</p>

<p>I am using Oracle.DataAccess in my code.</p>

ODAC xcopy will get you away with about 45MB.
http://www.oracle.com/technology/software/tech/windows/odpnet/index.html