  We derive the effective potential for the Standard Model Higgs-boson sector
interacting with Kaluza-Klein excitations of the graviton ($h_\mu^{\nu n}$) and
the radion ($\phi$) and show that {\it only} the Standard Model vacuum solution
of $\partial V(h)/\partial h =0$ (h is the Higgs field) is allowed. We then
consider the consequences of the curvature-scalar mixing xi R \Hhat^\dagger
\Hhat$ (where $\Hhat$ is a Higgs doublet field on the visible brane), which
causes the physical mass eigenstates h and $\phi$ to be mixtures of the
original Higgs and radion fields. First, we discuss the theoretical constraints
on the allowed parameter space. Next, we give precise procedures for computing
the h and $\phi$ couplings given the {\it physical} eigenstate masses, mh and
$\mphi$, xi and the new physics scales of the model. We show that LEP/LEP2 data
implies that not both the h and $\phi$ can be light. In the allowed region of
parameter space, we examine numerically the couplings and branching ratios of
the h and $\phi$ for several cases with $\mh=120\gev$ and $\mphi\leq 300\gev$.
The resulting prospects for detection of the h and $\phi$ at the LHC, a future
LC and a $\gam\gam$ collider are reviewed. For moderate $|\xi|$, both the
anomalous $h\to gg$ coupling and (when $\mh>2\mphi$) the non-standard decay
channel $h \to \phi\phi$ can substantially impact h discovery. Presence of the
latter is a direct signature for non-zero xi. We find that $BR(h \to \phi\phi)$
as large as $30 \div 40 %$ is possible when $|\xi|$ is large. Conversely, if
$\mphi>2\mh$ then $BR(\phi\to hh)$ is generally large. The feasibility of
experimentally measuring the anomalous gg and $\gam\gam$ couplings of the h and
$\phi$ is examined.
