You'll need to be using the latest Komodo IDE 6 or later.
You'll need to install the Oracle Instant Client libraries (versions required per platform are below). The Oracle Instant Client library is provided as a free downloadable file from the Oracle web site:
Oracle Instant Client 11.2 for Windows and Linux Oracle Instant Client 10.2 for Mac OS X (10.5 and higher only)
In Komodo, click on "Go to Anything", then navigate to "Packages" and search for "Oracle", then install "Oracle Database Explorer" by pressing enter on it or double clicking it. Once installed, Oracle will be one of the available databases to which you can add a connection to. Alternatively, you can install the add-on by downloading/saving the xpi file locally and then opening this xpi file from Komodo's File > Open dialog.
Version 1.0.1: Support Komodo 11.* Version 1.0.1: Support Komodo 10.*