To use Unicode and IPA on OS X, follow these steps:

• Install a recent copy of CLAN.
• If you need to work with older non-UTF CHAT files, you can convert them to UTF format using CLAN's CP2UTF program.
• This website from Will Styler at UCSD provides excellent directions on how to download, install, and use SIL IPA fonts and the IPA Unicode keyboard for OS X.
• The IPA Unicode keyboard works with any full Unicode font such as Arial Unicode. However, the Charis SIP IPA Font is somewhat better, because it allows for somewhat more options. With the IPA Unicode keyboard selected, you can still type in standard Roman on the main line, and you have the availability of IPA for the %pho line through use of the "dead keys" or prefix keys in the IPA keyboard.
• When entering IPA on the %pho line, you will find it annoying to have to switch out of the IPA keyboard to type the %pho header. However, if you go to System Preferences / Keyboard / Input Sources, you can check the box for "Use the Caps Lock key to switch to and from last used Latin input source". This will allow you to switch back and forth from IPA to the U.S. keyboard or some other Latin keyboard.