Every time I setup a machine with Oracle i beccome mad finding the correct Oracle Client, seen all the differences between the various versions, on some cd lost somewhere in the office. At the end i always download all the N Gigabytes of full setup just to install the client for odbc or jdbc and i suffer for a while configuring the connection...
Oracle Instant Client works from version 9i!!! For previous version you should come with the oracle installation CD!!!
I founded then the Oracle Instant Client, that seems to be the final answer to this chaos. I downloaded it from Oracle, downloading the ODBC Supplement and the required Basic Lite version.
I extracted all the stuff inside a directory (D:\Oracle\InstantClient) that i added to global PATH environment variable as required. Then i went there and tryng to run the "odbc_install.exe" i received the infamous
Could't find Oracle Instant Client in present directory.
What does that means? I founded that the "Basic Lite" installation has some bug. Some missing files that really matters only for the executable...
Look at the file list. You can find oraocci[some number].dll, for me is oraocci11.dll. Now create into the directory where you installed everything an empty file and rename it to oraociei[some number].dll, for me is oraociei11.dll.
Now run the odbc_install and... MAGIC! Everything works as expected!!!