Here's a trick that sometimes works (depending on the vehicle's 
under fender clearence)---With the car jacked up and on sturdy 
jack stands (shocks already removed, and brake hose and tie rod 
end disconnected) put a floor jack under the lower control arm 
to support it. Then remove the bolts that attach the inner shaft 
of the upper control arm (where it attaches to the chassis). This 
will then allow you to flip the entire upper arm and steering 
knuckle outward. Now you should be able to lower the jack carefully 
and remove the spring. I usually do this without using a spring 
compressor, but you may want to. Please be careful!! -ANT 

(ed note:)

 The above would be interpreted more clearly by supporting the entire
car on 4 jackstands.  Getting the rear axle higher than the front would
transfer most of the weight to the front springs, assuring they get 
compressed enough, by the jack,  to remove the spring.  Make sure you 
give yourself enough height in the front to allow the lower arm to swing 
free enough to allow the spring to fall out.  Replacing the spring is 
naturally in reverse order of sequence.