With media attention focused on other Middle Eastern protest movements and revolutions, the Palestinians feel marginalized.
That makes perfect sense, however, I think this is a short-term problem for them. The occupation of the West Bank and Gaza is a rallying cry for most in the Middle East, and is one of the few issues that has widespread support in the Arab streets and in the Arab governments (the only other I can think of is a general anti-Americanism; and the two are most definitely related).
Once things settle down and functioning governments emerge in Egypt and Libya and Syria, expect the Palestinian cause to be taken up again with more fervor than ever before. In short, the Palestinians need patience. If the Arab Spring lives up to its potential and installs governments that actually represent their respective people's opinions, then Palestine will not be forgotten. It will just take time.