I've work with a number of organisations looking to address the same issue. Due to regulatory issues or just a low risk appetite, each organisation has gone down the enterprise solution level, so that is the point of view I will add advice from.
Each time one company has been the front runner for the provision of the service and this is a US based company called - Good Technology with their "Good for Enterprise" solutions.
They offer "Enterprise-Grade Security and Management for iPhone, iPad and iPod Touch"
- Safe access to corporate email, contacts, calendar, Intranets, and Web applications on iOS devices.
- On-device encryption. Which protects the data from the device.
- Ability to apply corporate policy templates.
And in terms of your question, offers the ability to perform a remote wipe of the data. With Good, the enterprise data is the only data wiped. Which if you are in an organisation that supports personal device use is a great option.
On the downside, all data passes through the US based network operations centre. So you may need to understand if there is any issues for you as an organisation. Also as this is an enterprise solution, so cost may also be a barrier.
Hope this helps.