It turns out there's now a Mac-only "Mavis Beacon" product sold by "Software MacKiev" (Ukranian Mac contract software development) and another product (XP/Mac) sold by "Encore Software". The Encore Mac product is buggy and unsupported, the MacKiev version sounds a bit more promising.
it seems the current products are both descendants of a common ancestor that passed through a number of corporate labels including Software Toolworks / Mindscape, Broderbund, and The Learning Company .
What a mess. How did that happen? For that matter, what happened to all of the pretty good educational software produced by all of those companies? How did it all die, without true replacements (the closest things today are Flash apps on commercial sites that do child marketing)?
... Softkey ...purchased The Learning Company for $606 million in cash and then adopted its name...Brøderbund was purchased by The Learning Company in 1998 for about US$420 million in stock...
In a move to rationalize costs, The Learning Company promptly terminated 500 employees at Brøderbund the same year, representing 42% of the company's workforce.
Then in 1999 the combined company was bought by Mattel for $3.6 billion ... Jill Barad, the [Mattel] CEO, ended up being forced out in a climate of investor outrage.
This kind of churn is death to software. Software needs continuity to survive. The cycle of acquisition and 'rationalization" creates zombie software that staggers on, brainless, for years ... then dies.Mattel then gave away The Learning Company in September 2000 to Gores Technology Group, a private acquisitions firm, for a share of whatever Gores could obtain by selling the company. In 2001, Gores sold The Learning Company's entertainment holdings to Ubisoft, and most of the other holdings, including the Brøderbund name, to Irish company Riverdeep. Currently, all of Brøderbund's games, such as the Myst series, are published by Ubisoft...
The tech bubble made a few people rich, and it destroyed a lot of good products. Not to mention costing Mattel's shareholders quite a few pennies.
After the tech bubble burst came 9/11, then the great asset bubble and, not least, the Bush administration. One, two, three, four. No wonder America is reeling.
 At one time Mavis Beacon was sold under the Broderbund name, but by that time Broderbund might have been owned by Riverdeep. I include this story as an example of all the things the tech bubble killed.
Update 4/30/10: I bought the MacKiev product. It came with a solid, richly photographed manual with the name "Broderbund" on the front cover. This team is proud of their work. The manual included some interesting background on how Software MacKiev ended up doing their own OS X version:
Update 6/8/2010: I've received a few more details. The "Encore" versions of Mavis Beacon for OS X are arguably fraudulent. They're not designed for the current OS. Looks like "Encore" bought up some discarded software assets ...
Mavis Beacon Teaches Typing was created more than twenty years ago, and was first published in 1987. Software MacKiev’s involvement goes back to 1998 when our company developed version 9 for the Macintosh — both the US and UK editions. Then, a decade later, we had the opportunity to get involved with Mavis Beacon again — this time as the developer and publisher of a new generation of Mavis Beacon software for Mac OS X. We are so pleased and proud to be bringing the kind of quality you’ve come to expect from the creative labs of Software MacKiev to this new edition.
... Software MacKiev develops and publishes only the Mavis Beacon Teaches Typing 2008 and 2009 Deluxe, International, and School Editions for Mac OS X. The previous versions of Mavis Beacon were made for really old Macs with OS 9 by a company called Broderbund. A company called Encore has since taken over the broderbund.com Web site and continue to distribute the outdated software, which — as you point out — doesn’t work as it should...