Can you please suggest some good tutorial that would help me to understand the layouts used in vlsi design i.e., how can i retrieve circuit schematic from layout diagram
You can read "Modern VLSI Design" excuse me i forget tha author name. Other Books is "VLSI Engineering" of Dillinger, and if you speak spanish you can read "Circuitos Integrados de Aplicacion especifica ASIC" of Deschamps.
you can read 'CMOS IC layout design by Dan Clien', its a good book for the begineers.
I hope there is no tool available to retrive schematic from layout.
I had used Tanner EDA before in my uni days..there's a tutorial bundled with the software..however im pretty much sure u cant go from layout to schematics..but u can verify your design using the LVS application..