There is a good book out there: A.I. Pressmann, Switch-Mode Power Supply Design.
There is another book: K. Billings, Switching Power Supply Handbook.
You can also go to the TI website and download the Unitrode power supply design seminars. You will find enough material to help you design your power supply.
**broken link removed**
I am assuming you want to build this to power your circuits and stuff, more like a general purpose power supply right?
You can do it without isolation or with isolation, I suggest going with isolation as you'll be testing all your circuits with it.
Just get a transformer with the required power rating and use a buck converter or single-leg switcher, which is better in your case as your load current is rather high.
Or, you can simply get a Computer SMPS/PSU and use it like crazy. It can source more current than your requirement and is safe too.
You don't need to do study SMPS circuits for such simple designs, just refer some standard power electronic converter textbooks for DC-DC converters. After you pick one, come back here and post specific questions that can help you finish your project. All the best.
U can go to power integration site http://www.powerint.com/ and download the software they provide.Check all the devices .Whatever wattage required accordingly select the device.Lots of design reports are there on site.