Your 'Big Idea' Sucks
techdrawl.com
techdrawl.com
Better yet, use your customers' day-to-day problems as seeds for your idea. Better to scratch their itch than your own if you can. This would be a huge head start.
EDIT: found the link: http://news.ycombinator.com/item?id=737282
(the 'new' page is currently under attack...).
If you are confident about your product, build a simple prototype in a short amount of time and ship it for feedback.
Concurrent product development and customer development is the way.
In short: you can release a landing page before building, with a signup form for interested peeps, and you can release early and often.