Cortex M3 development tools PPA for Ubuntu
This PPA contains the openocd on-chip debugger and programmer software and a development toolchain for Ubuntu Lucid (10.04 LTS) and Maverick (10.10).
The STM32 series are Cortex M3 cores, so select the Cortex M-series, then Cortex-M3. The processors I have used are R1P1. A direct link to this document is here.