Chip thinks so, and so do we. DKIM is Yahoo, and Cisco's joint effort to create a sender authentication standard. Here's what chip has to say:

DKIM has a good chance of becoming an industry standard, because it is being released as open-source code, but also because of the size of the community that supports it, including Yahoo, GMail, and likely Earthlink. Plus, the DKIM protocol was just submitted to the Internet Engineering Task Force (IETF) who had commented publicly last fall that they had a preference for an encryption-based solution. With IETF support, many fence-sitters on the receiving side are likely to move forward. The IETF meets at the end of July in Paris.

We plan on adding DKIM support in our mail server as soon as the standard is in place. We already support Yahoo!'s DomainKey's authentication standard, which DKIM will replace.