If you've signed up as an Apple developer, go to developer.apple.com and sign in with your Apple ID. Visit your Member Centre page, and you should find links to your enrolled programs there. All that is required to begin receiving seed updates is a one-time change to your Software Update configuration, which you can find instructions for making at the downloads page for OS X Mavericks.
Be aware that both Mavericks and Yosemite now have public previews available for access by non-developers for testing, unlike iOS. These don't cost anything, but don't appear to be released quite as frequently as the release seeds for developers and, in the case of Yosemite, aren't even guaranteed to be available to all who ask. Cheers, Sabahattin -- You received this message because you are subscribed to the Google Groups "MacVisionaries" group. To unsubscribe from this group and stop receiving emails from it, send an email to macvisionaries+unsubscr...@googlegroups.com. To post to this group, send email to macvisionaries@googlegroups.com. Visit this group at http://groups.google.com/group/macvisionaries. For more options, visit https://groups.google.com/d/optout.