You can thank avsa for pestering me to make the Alarm service available on the testnet. You'll find identical version of the service deployed onto the testnet @ 0xb8da699d7fb01289d4ef718a55c3174971092bef.
I have a scheduling server hooked up to this instance of the alarm service so if you schedule a call there you can expect for it to get executed just the same as the main net. Reach out to me on gitter in the ethereum-alarm-clock channel if you have any questions or would like help integrating with the service.
I've also deployed the Canary contract to the testnet @ 0x6904acdd438acc322433f68fc64b9e3d5571f40c. As of this afternoon it was alive and well. I'll try to carve out time to get testnet canary info up on the the main Canary site as well.
Also, if you haven't seen, the latest Canary for the mainnet Alarm service is going to hit 100 heartbeats in about 6 hours (1 heartbeat every 2 hours/480 blocks). This canary has been alive for a little over 8 days marking a milestone in demonstrating reliability.
Meanwhile I'm working hard on on the next iteration which will include improvements to the scheduling api making scheduling calls easier and more intuitive. Time based scheduling is right around the corner, and I'm researching ways to implement triggering of calls based on events emitted by other contracts. Stay tuned.