I've spent a couple of days figuring out how program my STM32F4 Discovery board in OSX and though I would share here since it got a lot of attention on the DP blog.
My initial research lead me to texane's github where he created a linux version of ST-LINK. It doesn't support the STM32F4 yet, but there is a fork which is making good progress. I couldn't get either to work, which is when I turned to OpenOCD and Bus Blaster. A few minor modifications to the STM32F2 scripts and success. First time using the Bus Blaster and couldn't be happier.
Btw, it programs supper fast.
Here are the details
http://http://www.nabiltewolde.com/2011/10/programming-stm32f4discovery-board-with.html