You should see this information in the web interface under Data/Power over ethernet. Here's from one of my switches:
Total Power: 384W Total Power Used: 11.563W Total Power Available: 372.437W Average Total Power: 11.124W
There was a bug in one of the versions of firmware where it would stop providing POE to new devices. Not sure what version but if your not on the latest I would upgrade.
Thanks jhall, the firmware upgrade seems to have solved my problem. Was running 10.5 firmware and upgraded to 10.9.2 to clear issues. New devices are delivered power now.