Start another application

Hello.

I have a question, but it may not be a wxPython issue.

I made a help file as PDF format, and I'd like to call it from menu in
GUI application.
How can I start application (in this case:Acrobat Reader) related with
the file?

I managed to do it with os.popen2 by now, but it needs full path of
Acrobat Reader which depend on PC. I don't think this is smart way.

Windows XP, wxPython 2.4 for Python 2.3

TIA

- sS