Dharmesh Shah made mention about talking people to people who are interested in your domain about your product before releasing your idea. he talks about it in this video over at mixergy. Excellent video btw, located here.
I have an idea, there's some really big players in the industry right now but as i use their services i hate it. i feel as though i need these services but i can not stand the way they are currently done. i know how to improve these services and my idea does things completely differently.
So my question is how much information should i reveal to people and get feedback without someone stealing my idea or even the big players implementing it before i can get into the field.
I think in general people are over paranoid about idea theft. Execution is key, ideas they are a dime a dozen.
After you launch all your good ideas will be "stolen" by your competitors anyway. I think that being open in general will give you the advantage of getting better feedback and in turn launching a better product.
Keep in mind, no big player is going to wake up one day and "do things completely differently". They are heavily invested in their current way of doing things and will not just chuck it all out on a whim.
You may have an excellent idea, something that people will agree would be very useful, but, if it requires people to change how they operate, odds are you face a very tough uphill battle. That is the execution part.
Unfortunately it is difficult to get people to change how they operate, even if they are is a different way, due to their own inertia.
So, you may find that though people may like your idea you may need to break it into phases, to help move people slowly from how they are doing things currently to moving to a new way.
For a simple example, if Apple had brought out the iPhone before the iPod it would probably have failed, but they brought an iPod then an iPod that could go on the web, then the iPhone.
You really can't. I think you need to tap down expectations for yourself and your team.
There is no way to ensure success, but there are ways you can find out if there is a market for your product before you even write a line of code. I strongly recommend reading Eric Ries' blog Startup Lessons Learned, particularly the Lean Startup posts. Also, I would read Steve Blank's blog, especially the posts covering Customer Development.
If you are on twitter, follow the #leanstartup hash tag too.
There are a few more blogs on Customer Development, but these are the best places to start.