How Would You Launch a Dual-Licensed Product?

tdbp asks: "My startup company has just released its first product, but since it is made up of geeks without a clue about marketing strategies, and we are looking for suggestions on how to launch a product with spam-free methods of searching for possible customers. The product is a dual-licensed development tool, so the main targets are C/C++programmers and system integrators. Our plan is to build a community of developers around the GPL version of our product, and to use this base of users to promote the product to people of higher rank with more decisional power, who could eventually buy a commercial license or support service. Do you think this is a reasonable business model? Do you have any suggestions on how to promote the tool or find companies interested in it?"