If you have two, you're on a BES, right? The browser one should work (through your company's network), but
Go to http://instantemail.t-mobile.co.uk
Register if required/Log in
Go to Profile page
Click to send yourself the "Internet Browsing Service Book".
You should then wind up with the 'web n walk' browser - T-Mobile UK's brand for the BB Internet Browser. The other one is configured to go through T-Mobile's WAP gateway so some sites have problems.