You can register for races for the 2009 New Balance Boston Twilight Series here.
Be advised that entries close at 6PM the Thursday before race day.
Choose a race date at left (or above) and then choose the event for which you would like to sign up.
Once you have added all the entries, proceed to checkout and pay with Paypal.
Note: You do NOT need a Paypal Account to enter a race. You can pay with a credit card. After you click on "Checkout with Paypal", click on the link on the left that says: Don't have a PayPal account? No problem, continue checkout." There, you can pay with a credit card.