The MessageLabs Instant Messaging Security Service looks to provide businesses with a level of usage control, reporting and monitoring that both reduces threat levels and also recognizes the ubiquity of these formerly consumer technologies as business tools, despite their vulnerabilities.
I was particularly struck by MessageLabs' assertion that IM usage policy-building tools are built into the service.
The service covers IM clients from AOL, Yahoo and Microsoft. A free trial is offered. Ultimately, the service will be billed per user per month.