[wombie]

to create a solid heart shape with splines you would first create a closed path in the shape of a heart. The shift + scale it down to create a couple of smaller hearts. Then move the smaller hearts forward in 3d space. next you need to
select one and choose cross section and select the others, this will join them together with lines. Once you have done that you can change the points to be bezier curves and tweak them into a nice smooth shape.

To end you add a surface modifier. you can then either convert to edit poly or add an edit poly modifier.

A few pointers would be that for the surface modifier to work all the sections in the spline cage have to be 4 sided. Also i find it easiest to create the whole cage with vertex corners and then convert to bezier. And to keep it simple as its a simple shape just model one half and mirror it afterwards.

Hope this helps some.