I can highly recommend the Logitech DiNovo Edge, and Umart here in Australia has it at $100 cheaper than everywhere else.
I posted a request on the official PlayStation Blog requesting them to allow us to bind keys / mouse functions to controller buttons, maybe if enough people mention it on the blog Sony might take notice...specifically you need the start button to really be able to use the web browser and you also need the zoom in and out buttons (R2 and L2) and the joystick clicks (R3 and L3)
Keyboard shortcuts are:
ESC = Circle in many situations
F1 = Triangle in many situations
Right Mouse Button = Triangle in many situations
F5 and Control R = Refresh the page in the Web Browser
In the web browser you can move backwards and forwards by holding CTRL and Mouse Button 1 and making a left or right gesture, but this is damn near impossible and I end up picking up the controller and using L1 or R1, so it would be nice to map those too...