  In this paper, I present a new set of synthetic spectral energy distributions
(SEDs) for young stellar objects (YSOs) spanning a wide range of evolutionary
stages, from the youngest deeply embedded protostars to pre-main-sequence stars
with few or no disks. These models include significant improvements on the
previous generation of published models: in particular, the new models cover a
much wider and more uniform region of parameter space, do not include highly
model-dependent parameters, and include a number of improvements that make them
more suited to modeling far-infrared and sub-mm observations of forming stars.
Rather than all being part of a single monolithic set of models, the new models
are split up into sets of varying complexity. The aim of the new set of models
is not to provide the most physically realistic models for young stars, but
rather to provide deliberately simplified models for initial modeling, which
allows a wide range of parameter space to be explored. I present the design of
the model set, and show examples of fitting these models to real observations
to show how the new grid design can help us better understand what can be
determined from limited unresolved observations. The models, as well as a
Python-based fitting tool are publicly available to the community.
