From the Kinus brochure which AZ posted a link for:
Blackberry
The only company that provides a filter for Blackberries is J-net. This filter costs just a few dollars per month, but to use it you have to add a service called Enterprise to your plan.
A much cheaper solution is to use the everylock app to shut off the browser completely. Again, though, the bearer of the password has the power to unlock the browser.