If the application requires the Internet, you can force a registration and have it ping against a central database at your website once a month or something. Sun incorporates the ProcID into their licensing. When you run the application for the first time after install, it grabs the ProcId and wraps it into the Product key. You then go to the registration website, enter that number and a PurchaseID and it will verify the unique ownership and license count. If all is good, it returns an Activation Key. From there it's all good unless you move to another Processor. When they try to place it on a second system, the registration will see that it is already installed somewhere. If they want to change PC's then a phone call to release the license would be required.
If that's still too involved, there's always the "Have you paid your programmer today?" message after 30 days. If they don't enter a Registration Key, then it shuts off (like most share/trial ware).
Microsoft ties their licenses to the machine. Sun uses the Processor. Ultra-Edit, WinZip, Trillian, etc. use a PurchaseID with a ProductID (one of these keys will allow you to install on every machine in the building regardless of what the license states).
I guess it boils down to, how trusting of your customers are you? Are you worried about getting every cent possible or do you care that your software will be freely distributed through the company?
As for selling the product. First things first. Build a website with screen shots, descriptions and a demo. As for marketing the product... i have no idea... Google ads might be a good place to start.
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"...and did we give up when the Germans bombed Pearl Harbor? NO!"
"Don't stop him. He's roll'n."
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