Zabbix - Track, record, alert and visualize performance and availability of IT resources
NetCounter - NetCounter is a simple network traffic counter for EDGE/3G and Wi-Fi. It shows your data usage.
Datadog - See metrics from all of your apps, tools & services in one place with Datadog's cloud monitoring as a service solution. Try it for free.
Data Usage - Data Usage Monitor | Your guard against data plan overages.
NewRelic - New Relic is a Software Analytics company that makes sense of billions of metrics across millions of apps. We help the people who build modern software understand the stories their data is trying to tell them.
Call Meter 3G - Call Meter 3G is an app that acts as a monitoring tool for all your calls, messages, and internet data.