I recently purchased a 1992 Samurai that is so high that my wife needs a step stool to enter the vehicle. I noticed the leaf springs are installed on top of the axle housings. Is ths correct? If not, how much effort is required to relocate the springs under the housings.

No, somebody has placed the springs on top of the axle.  It is not too difficult to relocate the springs under the axle, but you might be better selling it and buying a more stock-like Samurai.  What size tire are you running?  Is the Samurai only driven on the street.  Post some pictures of said vehicle.

What Jonny hasn't mentioned is that "spring over" conversions can range from "fast & nasty" to very competently done - and reconverting it can involve reversing much or all of the work, so what you really need is to have the vehicle looked at by someone familiar with Samurais to determine what has been changed.

As he suggests you might be better off selling it - if it's a properly done conversion, it could be worth it.

Alot of folks do this so that they can run larger tires. Few folks buy them this way and want to change them back to stock. (Not that there is anything wrong with doing so.)

Moving them back under the axle takes a little work. Some of this depends on how your particular installation was done.

There needs to be spring pads for the springs to bolt to under the axle.

Your steering may need to be changed depending on has been done.

Your shock mounts may need to be relocated back to the original positions.

Your driveshaft may have spacers in it which should be removed.

Your brakelines might have been lengthened and returning them to a shorter length might make sense depending on how long they are.

It just depends on what has been done and these are a few things I can think of...

A photo of your Zuk underneath would help give a better description / diagnosis of what might need changed.

and besides that..... We Love TO See Zuk's.....