It's an easy fix, just let people change their user agent. That is, if it's an actual block and not some terrible version of Flash.
Failing that, you can set up a proxy that washes your user agent for you if you have a spare computer to route your ps3 through.
The real shocker (although not really shocking in terms of Sony) is the fact that they decided they would write their own browser instead of building on top of existing engines out there. I know they added the console zooming/etc for the controllers, but I imagine porting another browser to that UI rather then writing a new one would still have been easier.
Also, as an aside, the text input for the ps3 browser makes me want to hurt things. I can't even type in a full URL directly because it insists on trying to use text completion with a character limit. Never mind the fact that it can't even complete simple idioms like '.c' maybe suggesting '.com' for a URL? AAAAaaaaa rage.