I see it in MyriadPro. The Unicode is U+0259. It's also in Lucida Grande
Which version of MyriadPro Larry? I don't see it in MyriadPro Open Type 2.106. I see it on fonts like Arial, Colibri, Times. There's an article that talks about it: http://indesignsecrets.com/how-to-insert-a-schwa-or-other-phonetic-character-in-indesign.p hp
I have the version 2.102 OTF so maybe they changed it.