After months of anticipation, the day is finally here: Enrollment for the Medicare prescription drug benefit, officially called Part D, is now open. If you want coverage to start first thing in the new year, you should sign up before the end of 2005. But there's no need to rush; the initial sign-up period runs until May 15, 2006. Experts say you should make sure you fully understand how your current coverage (if you have any) works and carefully weigh whether it pays to pick a Medicare drug plan. And keep in mind that you may face penalties if you sign up after the enrollment period. The government's website (www.medicare.gov) and community senior groups can help you compare your options, which in some cases can be overwhelming.

Read more about Part D from U.S. News & World Report:

What's the deal with Part D?

How the new drug plan works

How to spot scams

How to pick a plan

How to get help