These directions I linked from the wiki page (and is included in the source, also linked from the wiki page) should cover everything necessary to build the source and program the device. Basically it uses the codesourcery gcc and openocd:
https://github.com/szczys/stm32f0-discovery-basic-template/blob/master/README.md
https://github.com/szczys/stm32f0-discovery-basic-template/blob/master/README.md
