I have connected a Digi Connectport X4 and several sensors (Temp, humidity, light) to pachube.
This gives me the ability to generate graphs and provide current and historical measurements to other applications in the cloud. I used the iDigi DIA and implemented a pachube post presentation to get the data into the cloud. It has been working pretty well, however I need to add some more robust error recovery code to make it more reliable.
Unfortunately the data stream has been offline for a while, so I have some work to do. By the time anyone reads this hopefully it will be back online.
The full pachube feed page is here.