The one million new Part D enrollees heading to pharmacies this month were offered tips by Medicare Rx Education Network. New enrollees who don't yet have their Rx card should bring their plan's proof-of-eligibility letter to the pharmacy. If they don't have the letter, they should phone the plan's customer service desk and ask for their ID number, along with numbers and addresses pharmacies can use for billing. Dual eligibles should bring proof of eligibility for both Medicare and Medicaid. Beneficiaries who aren't sure they have coverage yet can phone 1-(800) MEDICARE.