Christopher Jones has posted about the latest Instant Client release for the Intel chips running OS X:
Hot off the press, Kuassi points out that Oracle Instant Client for Apple Mac OS X (Intel x86) is now available from the Instant Client page on OTN. It's the latest 10.2.0.4 patchset.
The 10.2.0.4 release of Instant Client for Windows 32bit and Linux x86 have also been released.
The Oracle Instant Client is a lightweight version of the standard Oracle functionality that's not only smaller but allows installation of an Oracle client without having to do the full Oracle install.