What is the difference between clustering and quantization?
They are essentially the same. The generalized form of the Lloyd's algorithm is LBG which is used for vector quantization (VQ).You may use k-means for the purpose of vector quantization just like the LBG algorithm. In vector quantization, the input space is partitioned into a set of convex areas. They are also referred to as Voronoi regions or cells. If you look at here it says k-means (which is mostly used in computer science) is actually originated from VQ in signal processing as well as pulse code modulation back in fifties. 

If you want to implement VQ, you may directly use k-means algorithm. The original LBG algorithm is presented in the following paper if you are interested:

Y. Linde, A. Buzo, and R. M. Gray, ``An Algorithm for Vector Quantizer Design,'' IEEE Transactions on Communications, pp. 702--710, January 1980.