Choosing a free or open source software license

Update (6 years later!): Tools like choosealicense now exist!

I’m working on multiple pieces of future open source software at the moment, and I’ve got to the stage in development where I need to do some thinking about the license I choose for everything, due to the other open source software I’m modifying, building on top of, and linking against.

There’s a reasonably comprehensive and curated comparative list of licenses on Wikipedia. My problem is how the hell do I pick one, or more likely how do I pick the multiple licenses I’m going to need?

There seems to be a gap in the market for a service that recommends licenses to you, based on your understanding of the software you’ve written and the other software it interacts with.

I could then take those recommendations to a lawyer to get legal confirmation I was doing the right thing and using the right licenses, something that’s incredibly problematic in and of itself.

Will my lawyer understand the law? Is the law likely to change in the lifetime of my software, enough to facilitate a license change or changes, for better or worse? How do I work out the lifetime of my software? Do I need to track new versions of the license and will they supercede the text in the version I choose?

It’s such an incredibly hard thing to understand as a layman, even one that’s been exposed to open source and has used it for such a long time.