this is a small tut about using the new harmonic force, hope you will find it usefull.
Now set the following particle properties:
Is important to set the Newtonian damping value because otherwise particles will blow away 😉 but you are also free to experiment with the Harmonic damping factor, the rest length, etc. the final result should be something like an oscilating water like drop, all of this without particle fluids yet!
Note also that you should use a newer SVN revision than 25500.
here is the example .blend http://www.pasteall.org/blend/1384