We discuss possible observational manifestations of static, spherically sym
metric solutions of a class of multidimensional theories of gravity, which
includes the low energy limits of supergravities and superstring theories a
s special cases. We discuss the choice of a physical conformal frame to be
used for the description of observations. General expressions are given for
(i) the Eddington parameters beta and gamma, characterizing the post-Newto
nian gravitational field of a central body, (ii) p-brane black hole tempera
tures in different conformal frames and (iii) the Coulomb law modified by e
xtra dimensions. It is concluded, in particular, that beta and gamma depend
on the integration constants and can be therefore different for different
central bodies. If, however, the Einstein frame is adopted for describing o
bservations, we always obtain gamma = 1. The modified Coulomb law is shown
to be independent of the choice of a 4-dimensional conformal frame. We also
argue the possible existence of specific multidimensional objects, T-holes
, potentially observable as bodies with mirror surfaces.