Do you mean really Rietveld analysis (for crystal structure determination from powder diffraction data), or full pattern refinement (for quantitative phase analysis)?
Bruker run a series of workshops throughout the year. Most are based in Karlsruhe but they apparently also run them in Madison WI and Freemont CA in the USA.
Alternatively Durham run a Powder Diffraction and Rietveld School the most recent was in April 2014. Much of the tutorials is online - see link below
Hi All, probably Raja is interested in workshops to be held ONLY IN INDIA (although not explicitly mentioned in the question). I can probably understand the plight of an Indian Research Scholars (we do not have/get grants for attending workshops abroad, except for very very few who get DST travel grants for presenting papers in international conferences and ICTP).
Raja, as far as i know, Science & Engineering Research Council (SERC), now probably scrapped/renamed to Science & Engineering Research Board (SERB), under the DST (Govt. of India) used to fund SSCU Department (Solid State and Structural Chemistry Unit) at IISc Bangalore for SERC Summer School on Solid State and Materials Chemistry Workshop (google by that name) every 2-3 years, duration almost a month, where everything regarding solid state chemistry including all sort of characterization techniques, XRD, Rietveld, Solid state NMR, Raman, FTIR, SQUID, etc etc. used to taught properly with practicals. I am eagerly waiting for this one since last 2 years now, and no sign of it in the IISc homepage this year too. The selection used to be highly competitive and only 25-30 participants were selected (mostly PhD research scholars and some faculty), and provided with on-campus stay without any fees.
This is probably the best resource you can get in India. Alternative you contact Prof. T.N. Gururow or Dr. Sivakumara (both of SSCU). They are the experts of Rietveld, and they were the actual faculty for for Rietveld in that summer school.
If you get any information (through any of your friend in IISC or otherwise), please tell me too.