Focus Magic is magic indeed.
I've used it with great success for minor focus and motion correction.
But really, it is Math not Magic; what it does is to mathematically return out of focus disks of light into points of light by a process called deconvolution. This process is fundamentally different from other "sharpening" methods which mask rather than correct focus errors.
In principle Focus Magic can turn a soft lens into a sharp one. In practice it actually does that - it can't correct a coke bottle of course, but it does a fine job for minor softness. Here's an example from a wide open Soligor 200:2.8 lens:
And another snagged from the web.
I use it both stand-alone and as a plugin to Paint Shop Pro.
Dave