Canova's works are well known -- the most famous is his "Paolina Borghese" (which Canova labeled "Venere Vincitrice" -- "Venus the conqueress") on display at the Villa Borghese Museum here in Rome. Other Canova works grace the best museums worldwide. The Tadolini sculptors are less well known outside scholarly and artistic circles, but they were worthy and quite successful successors of the neo-classical tradition that Canova started. Their works are spread around the world: three castings of Adamo's Simon Bolivar Equestrian statue are in Caracas and Lima and in Piazza Bolivar next to the Modern Art Museum in Villa Borghese in Rome; Scipione's St. Michael is at Boston College (Gasson's Rotunda); Giulio's Leo XIII is in St. John Lateran here in Rome; Enrico's statue of St. Frances Cabrini is in St. Peter's -- and there are numerous others.
The Canova-Tadolini Museum is operated by the nearby Gallerie Benucci. It's very easy to find -- on the west side of the street and halfway between Piazza di Spagna and Piazza del Popolo, and the Babuino statue is right next to its front door. It is open Tuesdays through Saturdays from 10 AM to 1 PM and from 3 PM to 7:30 PM. The ticket costs IL8,000 with a reduction to IL6,000 for groups of ten or more. The upper levels are not wheel-chair accessible, but there is a great deal to see on the ground floor. There are no restrooms.
Canova, Come Home -- L'Espresso (in Italian): http://188.8.131.52/tempo_libero/mostre/archivio/canova/canova.shtml
Canova's greatest hits from "1200 anni di scultura italiana": http://www.thais.it/scultura/canoanto.htm
P.S.: The Venus statue, a nude portrait statue of Paolina Borghese (the sister of Napoleon Bonapart), is still displayed in the same room for which it was made in the Villa Borghese Museum. Like some other famous Roman sculptural works, it was originally mounted on a pivot so it could easily be turned for viewing in natural light from the window. The pivot was removed during the museum's renovation in the 1990's, when modern lighting was installed.