Rock,
you are not going to achieve this with solidworks if it is the animation you are looking for... if you are interested in seeing how the forces edforme the spring then you need to be looking at an fea solution for that scenario.... SWX2003 has something called CosmosXpress that will handle simple things like this, BUT it does not do assemblies if you want to do assemblies you need to buy the add-in CosmosWorks or another FEA solution to help you with this.
if you could care less about the numbers (stress/strain,etc) and you want to simulate the motion of the spring then you could do it with multiple configurations and switch through them "frame by frame" so to speak... in other words you could take a screen shot of it in each configuration and save it to either an animated gif file, or perhaps use something to create an avi feame by feame.... very time consuming though because you need to make MANY frames to make it look good...
I suppose that you could define the spring using an incontext relationship but I am not sure what type of spring you have their... lets say we have a coil spring which is basically a sweep around a helical curve.
I would draw a construction line "in context" with the assembly to show the total spring height between the other components. Then you can put a reference dimension on it.
Create your helix using "height" and number of turns. give it a height and the number of turns and complete the helix.
Create an equation that drives the height dimension in the helix definition and make it equal to the ref dimension
create your sweep profile on a plane normal to the curve(helix) then sweep away
if you move the assembly and you have sonctrained the construction line correctly the model should update and show the spring in different heights AFTER you rebuild the assembly... its still not going to be "video quality" though
hope that helps a little
Regards,
Jon
jgbena@yahoo.com