They can, but I live in Finland and all our phones are better then your
phones. :P
Depends A LOT on the phone. To bring up different pages depending on
the phone we use pywurfl a very nice too that has a large database of
phones and what they can support. (You can even add your own phone
support too.)
Many phones today are starting to move to a Javascript UI (The palm pre
for example), crazy enough.
Regards,
Jason Brower