The bullet points sent tonight by the White House:
Undocumented immigrants would not be able to buy private insurance on the exchange. Those who are lawfully present in this country would be able to participate.
Undocumented immigrants would be able to buy insurance in the non-exchange private market, just as they do today. That market will shrink as the exchange takes hold, but it will still exist and will be subject to reforms such as the bans on pre-existing conditions and caps.
Verification will be required when purchasing health insurance on the exchange. One option is the SAVE program (Systematic Alien Verification for Entitlements) which states currently use to make sure that undocumented immigrants don't participate in safety-net programs for which they are ineligible.
There would be no change in the law that requires emergency rooms to treat people who need emergency care, including undocumented immigrants. There is already a federal grant program that compensates states for emergency room costs associated with treatment of undocumented immigrants, a provision sponsored by a Republican lawmaker.