How do I ensure data security on my company's mobile devices?

Do you need security on your mobile devices? That depends on what type of access and information your devices have on them. If a rogue user could potentially access your network with one of your mobile devices or there is any sensitive data or email on these devices, then yes you need to secure these.

From my experience the best way to do this would be to use PKI enabled devices that require a physical token such as a smart card to unlock. You can find laptops with a smart card reader built in. You can encrypt the entire contents of the PC and use PKI to unlock the data. Without the physical token and its associated PIN the data would be relatively safe. The same would go for a mobile phone. There are smart card readers for Blackberries that can be used to afford the same level of protection to those devices.

Having said that, physical access can go to the root of all security. If someone is allowed unsupervised physical access to any device, with time could circumvent any security measures. The most effective means of keeping data safe is to not allow it to be stored on any device that leaves controlled areas. This would mean that remote users would have to use a VPN to access the corp network to gain file access and nothing would be stored on the PC hard drive or local on a hand held device. This is not as user friendly and does impact performance.