Obtaining ¹³C spectra is more complex than for proton NMR. This is primarily because of the low isotopic abundance of ¹³C in nature. It exists in only about 1.1% abundance. ¹²C is has nuclear magnetic moment and so cannot be used. Since the abundance of ¹³C is so small, spectra take much longer to obtain, although their usefulness is determining the carbon framework of a molecule is extremely valuable.

Not only do we get information about the number of carbon atoms in a sample, we also get information on how those atoms are arranged. The normal mode of ¹³C operation is with proton noise-decoupled mode. This experiment gives us a single sharp peak for each type of carbon in the molecule. The spectrum of methyl acetate makes this clear.
As you can see from the spectrum there are three peaks, corresponding to the three carbon atoms in the molecule.  You'll notice that they do not all appear in the same place.  The location of a particular peak is dependant on the chemical shift.  Many factors affect chemical shift of a peak, mainly it can be explained by considering the electron density around the nuclei involved. The higher the electron density around the nucleus, the further downfield (shifted to the left) the peak will appear in the spectrum.  The ¹³C chemical shift table is shown below.
 

If we go back to methyl acetate, the three peaks appear at very different chemical shifts.  The peak furthest shifted downfield (at 171 ppm) corresponds to the carbon of the C=O group. This is because oxygen is very electron withdrawing and reduces the electron density around the carbonyl carbon.
The other two peaks correspond to the methyl carbon atoms. The methyl carbon adjacent to the ether oxygen atom is shifted furthest (52 ppm) because of oxygen's electronegativity. The remaining methyl carbon appears at 21 ppm since it is adjacent to a carbon atom.