For a project I’m doing at work, that I hope will eventually be open source, I needed to have protobuf compiled for iOS. A colleague of mine showed me how it had been compiled on iOS 4, using these scripts, but with iOS 5 I ended up with binaries compiled for the arm architecture instead of the armv7 architecture.
Be aware that the iOS 5 SDK actually ships with a version of protobuf, but it’s a bit old, being version 2003001. And it only ships the binary, not the headers.
After running this, you should have a directory called /tmp/protobuf/arm that is compiled for your iPhone or iPad with the armv7 architecture. Copy that into your project and start using protobuf