The hilton offers a limo service, but its not cheap.. call them for details.. if I remember right its about $120.. although rates have changed alot since I was there..

The easiest is simply to rent a car at BRU, its a straight drive (follow signs to antwerp) then follow signs to historical town centre, then to Groenplatz parking.. the hilton has pay-parking in the basement of GroenPlatz and a private elevator to the lobby..