export PYTHONPATH=$PYTHONPATH:/home/fred/SciParam-0.9.0/
in your ~/.bash_profile, etc. If you use Windows NT, 2000, or XP, then set your environment variables by right-clicking on My Computer and selecting Properties. If you use some other version of windows, you'll need to set the variable at a command prompt, or in autoexec.bat, with the 'set' command.
If you'd like to install SciParam system-wide on your machine and into the default PYTHONPATH, you can use setup.py to do so:
# python ./setup.py install
Be sure to run setup.py with appropriate privileges (root under Unix).