Are there any legal plugin's that will allow Lisp to work in autocad lt.

Sadly no.Best you can do is create macros using scripts.

If you really need lisp capability take a look at nanoCAD.  I think it is 1) free and 2) supports some form of lisp.  At one time there were add-on programs that gave AutoCAD LT lisp capability but AutoDesk threatened to take the makers to court unless they folded up shop.  Neither company had deep enough pockets to slug it out in court with AutoDesk so they capitulated.

Thanks everyone.