Luis Villa is running a great series on what GPLv3 means for developers. Here's a snippet:
Q: I'm a developer, and my current code uses GPL v2 - should I update to the v3?
A: Probably. While the license does not include any huge wins for all developers that would make an upgrade obvious or mandatory, there are small wins here for virtually anyone who seeks to have a functional FLOSS project. In particular, every developer should appreciate the improved (if still imperfect) patent protection, the ability to copy and paste APL-licensed code into your code, and the internationalized legal language, offering them stronger protection outside the US's copyright system.
In addition, those developers who object to TiVo-ization of their code, or to the use of their code in a DRM system, will like those sections of the new license. As I mentioned yesterday, these sections of the code may not be perfect, but they should go a long way towards ensuring that users of your code always have the right to access it and modify it- something that wasn't necessarily clear under the old license.
You can find Part 1 of his series on the blog. Remember: Luis = (developer + lots of open source experience). This doesn't make him an expert, I guess, but it does make for informed writing.