Eudora is dead. Long live Eudora.
More info in the press release. Looks like there are already plans to blend Eudora and Thunderbird into a hybrid client:
The Penelope project’s intention is to join the Eudora user experience with the Mozilla platform. We intend to produce a version of Eudora that is open source and based on mozilla and Thunderbird. It’s *not* our intention to compete with Thunderbird; rather, we want to complement it. We are committed to both preserving the Eudora user experience and to maintaining maximum compatibility, for both developers and users, with Thunderbird. It is our goal to build a single development community around Thunderbird and Eudora, so that both mailers advance faster than they previously have.”