You'll now be able to share content across 2 PSPs or 3 PS3s.
Sony's PlayStation Network is getting a bit stricter starting November 18th. The number of devices allowed to access a game on the same account is being cut down.
In a week and a half PlayStation Network titles will only be accessible on up to three PlayStation 3s and just two PlayStation Portables. It's a pretty reasonable number, but those owning multiple systems are certainly going to be upset.
One of the big problems, of course, is that your old PS3 or PSP that you've sold or has broken will still show up as activated. Sony is planning on a website that will allow you to deactivate these, but in the meantime you can contact customer service to take care of it.
Source: PlayStation Blog