What is the vsepr shape of H2CO3

The lewis structure looks something like this:

O=C-O ... | ... O

with the hydrogen atoms bonded to two of the Oxygen atoms. There are two other resonance structures which means that a double bond does not actual exist in the molecule. Instead there's a pair of delocalized electrons that span the entire molecule. This means that all three bonds are actually equal and thus the molecule has a trigonal planar geometry. You can also tell that it's trigonal planar because the central atom is sp2 hybridized.