Research in Motion Ltd. said Thursday it will offer for the first time a Macintosh-based e-mail and calendar application for its BlackBerry handheld devices.

RIM has signed a licensing deal with Information Appliance Associates to offer free downloads of the PocketMac program for BlackBerries, and to later integrate the software with the handhelds, officials with the companies said.

The move deepens RIM's rivalry against Palm Inc., which for years has provided synchronization software for users of Apple Computer Inc.'s Mac computers with its line of handhelds and Treo smartphones.

The Mac OS X operating system even includes a free program called iSync that lets users synch their address and calendar information from their Macs to Palm handhelds.

By comparison, BlackBerry users with Macs had to resort to third-party providers. For instance, they would have to find PocketMac, a program for synching e-mail, contacts, and calendar information from a desktop to handhelds, on their own and pay $29.95 to get the program installed.

Now with the licensing agreement, Mac users will be able to get the PocketMac program directly from RIM — for free, starting in February.

For Apple, the deal reflects its growing influence and could lead to more interest from corporate customers, which predominantly operate in Microsoft Corp.'s Windows-based environment. Business users constitute RIM's core market.

"There is significant interest in BlackBerry from Mac users and we look forward to delivering PocketMac for BlackBerry to customers around the world," said Mark Guibert, vice president of corporate marketing at RIM.

Terms of the deal were not disclosed.