Search on Your Own. You can certainly search the patent database to see if someone has registered a similar idea - we prefer Google's patent searching system over the USPTO database. And you can review the trademark database - lately we like Trademarkia.com more than the USPTO (although they each have searching idiosyncrasies).
Great Ideas R Us. The Dear Rich Staff respects you for coming up with one great idea and hope you come up with more. But keep in mind, there's a reason for Thomas Edison's inspiration/perspiration equation. As Edison himself acknowledged, his success was primarily attributable to being a "hustler" rather than to any of the great ideas he instigated, cajoled or "borrowed." In other words, coming up with great ideas is not the hard part; the challenge is in selling your brainstorm.