[Brian]

Use the steps in the "setting up a computer-to-computer network" topic of Mac Help to directly connect your Mac to the iPhone - does sync work now? If so, something about your wireless network configuration changed that's preventing OmniFocus on the iPhone from connecting to your Mac.

If the computer-to-computer connection isn't working, I'd start looking to see if the firewall settings in System Preferences on your Mac had changed, or if Little Snitch or some other software that could be blocking the connection was active.

If *that* doesn't turn up any results, send an email to the support ninjas and we'll be happy to work with you and figure out what's going on.