  The properties of light leptoquarks predicted in the context of a simple
grand unified theory and their observability at the LHC are investigated. The
SU(5) symmetry of the theory implies that the leptoquark couplings to matter
are related to the neutrino mass matrix. We study the resulting connection
between neutrino masses and mixing parameters and the leptoquark decays, and
show that different light neutrino hierarchies imply distinctive leptoquark
decay signatures. We also discuss low-energy constraints implied by searches
for charged lepton flavour violation, studies of meson decays, and electroweak
precision data. We perform a detailed parton-level study of the leptoquark
signals and the Standard Model backgrounds at the LHC. With the clean final
states containing a di-lepton plus two jets, the QCD production of the
leptoquark pair can be observed for a leptoquark mass of one TeV and beyond. By
examining the lepton flavor structure of the observed events, one could further
test the model predictions related to the neutrino mass spectrum. In
particular, b-flavor tagging will be useful in distinguishing the neutrino mass
pattern and possibly probing an unknown Majorana phase in the Inverted
Hierarchy or the Quasi-Degenerate scenario. Electroweak associated production
of the leptoquark doublet can also be useful in identifying the quantum numbers
of the leptoquarks and distinguishing between the neutrino mass spectra, even
though the corresponding event rates are smaller than for QCD production. We
find that with only the clean channel of mu+ E_T jets, one could expect an
observable signal for a leptoquark masses of about 600 GeV or higher.
