According to a post on both the Star Trek Online and Champions Online sites, lifetime subscribers to each game will automatically receive beta access to Neverwinter as a gift from Perfect World Entertainment.

Greetings Champions!

We are happy to announce that all Champions Online Lifetime Subscribers will be receiving access to the Neverwinter Closed Beta test*. *When this testing phase begins, invites will be doled out to Lifetime Subscribers over the course of the test.

Find out more about Neverwinter.