Yes, you can. For some reason I can't remember how though, but I just did it 2 weeks ago right after I got my PS3 (haven't really used the browser though)
If no one replies, I'll look tonight and figure it out for you. I don't remember it being that hard though to find.
Speaking of the browser though, how capable is it? I mean, what can't it do that Firefox/IE can, as far as technologies (forms, SSL, video, flash, silverlight, etc...). I'm debating on getting a wireless keyboard for mine, but need to play with it more to see if it's worth using it at all, or if I should just stick to my laptop.
Edit: Looked it up on another site that says to press triangle and the options for resolution are in the view and tools menu.