Spawn new process -> get pid

[breal]

I have a soap server written in Python that acts as an intermediary
between a web service and an InDesign server.  The indesign server is
non-threaded, so when all instances are used up I want to create a new
instance, get the pid, use the process, then kill it.

What is the best way to do this?  I don't want to replace the current
process with the new one which is looks like os.exec* does.

Thanks.