  The physical properties of almost any kind of astronomical object can be
derived by fitting synthetic spectra or photometry extracted from theoretical
models to observational data. This process usually involves working with
multiwavelength data, which is one of the cornerstones of the VO philosophy.
  From this kind of studies, when combining with theoretical isochrones one can
even estimate ages. We present here the results obtained from a code designed
to perform chi^2 tests to both spectroscopic models (or the associated
synthetic photometry) and combinations of blackbodies (including modified
blackbodies). Some steps in this process can already be done in a VO
environment, and the rest are in the process of development. We must note that
this kind of studies in star forming regions, clusters, etc. produce a huge
amount of data, very tedious to analyze using the traditional methodology. This
make them excellent examples where to apply the VO capabilities.
