  We discuss same-sign dilepton resonances in the simplified model approach.
The relevant $SU(3}_Q^J$ quantum numbers are $1_2^{0,1,2}$. For simplicity, we
only consider a spin 0 scalar, which is typically referred to as a doubly
charged Higgs in the literature. We consider the three simplest cases where the
doubly charged Higgs resides in a singlet, doublet or triplet $SU(2)_L$
representation. We discuss production and decay of such a doubly charged Higgs,
summarize the current direct search limits, and obtain mass limits in the cases
of singlet and doublet for the first time. We also present a complete set of
updated indirect search limits. We study the discovery potential at the Large
Hadron Collider (LHC) with center of mass energies 7 and 14 TeV for the
dominant Drell-Yan pair production with $H^{\pm\pm}$ decay in the $ee$ and
$\mu\mu$ channels. We find that at 7 TeV, the LHC with 10 $fb^{-1}$ luminosity
can probe mass of the doubly charged Higgs up to 380 GeV assuming 100% decay to
leptons. At 14 TeV, the LHC with 100 $fb^{-1}$ luminosity can reach a mass of
up to 800 GeV.
