Mark Radcliff gave a talk at OSBC about making sure your legal strategy matches your open source strategy. One of the things he talked about and blogged about was how to pick a license. He mentioned 7 factors to consider when picking a license:

1. the sources of revenue
2. the type of product
3. business model
4. type of project
5. channels
6. type of community
7. competitors

One he forgot (although it may fit into community) is who is going to use the project and how. I know a company that released a cool product under the GPL to discover a year or so later that nobody was using it for fear of copylefting their own products. They changed the license to the LGPL and their user base and therefore their community grew rapidly.