/Edit TK: this thread is expired, it discusses workarounds for the obsolete, Java based MIOS Studio 1
MIOS Studio 2 works natively on Mac OS without workarounds:
Original Article from Adam:
Bob Lang, creator of Mandolane (/edit TK: previously called Plumstone), has update the Mandolane MIDI drivers for Java 1.5 and this will hopefully allow Mac users who are running Java 1.5 to run MIOS Studio.
Not being a Mac user myself, I haven't been able to test this. However, Bob has succesfully gotten MIOS Studio to run on Tiger by using Java 1.5 and his new version of Plumstone. Although untested, he has updated Plumstone in a way that should be backwards compatible with Java 1.4 and I have updated MIOS Studio to also be backwards compatible - therefore anyone running older versions of OS X and Java 1.4 are encouraged to also test this out. The latest beta version of MIOS Studio is available here, please note that some features such as the SysEx Upload and Memory Read/Write are not fully implemented yet.
If any Mac users can try this out and report their findings it'd be a great help. Also, please keep checking Bob's Mandolane site for any updates and/or official releases.
Update 2008-03-21: an alternative software is available here:
In distance to Plumstone/Mandolane it's free!
Update 2009-09-03: mmj has been discontinued, it doesn't work with 64bit Java, and it doesn't work under Snow Leopard (even when 32bit JRE is selected)
Please use Mandolane again