] Although Microsoft may continue to provide security and
] performance updates, no major new releases are planned,
] Microsoft Product Manager Jessica Sommer told CNET
] News.com. Sommer said that with the emergence of Apple's
] Safari browser, Microsoft felt customers were better
] served by using Apple's browser, noting that Microsoft
] does not have the access to the Macintosh operating
] system that it would need to compete.

Microsoft: No new versions of IE for Mac | CNET News.com