For years, I've been relying on other peoples services to establish a public IP address.
So what's the problem?
Well, like everything in the world of development, the weakest link is things beyond your direct control. Take my situation over the weekend.
I used a service to establish the public IP address of a server (to mock a dynamic DNS service). The IP was a dynamic one, so I needed the update. Problem was, the service is gone.
I ended up rolling my own. Introducing: My IP is...
Check it out if you have a second. It's pretty cool (for what it does - which isn't much). But, you've got the chance to get your public IP programmatically (should you need it). It has a few different endpoints, including JSON, XML, and Plain
The best part is... it's on Google App Engine, so you know it'll never (hopefully) go down. And the network traffic is so little that it'll never leave the 'free' tier.
Big Cheers to the Google guys!