I saw this excellent article this morning that covers 5 basic tools for doing file cryptography across platforms. Many of these tools are great solutions and we use them frequently with clients. In particular, we find True Crypt to be a very powerful and useful tool. Many client have embraced this solution for laptop encryption, leveraging the free price and benefit for compliance.
You can read more about these tools here.
Check them out and use the ones that fit your needs in your organization. They are great tools for keeping your business, your business.