are you using internet explorer? it might have trouble in other browsers... I get the fios online no problem. does it give you a message?
FiOS TV Online products will provide exclusive content from these current providers:
Turner (Adult Swim, TNT, TBS, Cartoon Network)
Yankees on YES
and to the best of my awareness, yes they are trying to get more online. they just launched flexview - that might be kinda cool, i haven't used it yet.