A version for Google's Nexus One and other Android handsets will be offered later this year, IBM said.
Also new this week at Lotusphere 2010: More IBM applications for BlackBerry users, who will get new clients for Lotus Quickr collaboration and Lotus Connections social networking. A client for Lotus Sametime instant messaging is already available.
BlackBerry-maker Research In Motion said it was licensing Connections for use among its own employees. IBM, meanwhile, announced that, for the first time, it would begin selling BlackBerry hardware to its corporate customers.
IBM and RIM are enterprise stalwarts, with many years of corporate IT sales. Not so for Apple's iPhone, which many IT departments view as an insecure consumer devices and don't allow them on their networks.
That could change with the introduction of Lotus Notes Traveler Companion. The plug-in allows iPhone users to see encrypted Domino e-mail as a link that, after the user enters their Traveler password, can be opened and responded to on the iPhone.
Exiting Traveler clears the decrypted e-mail from the device, leaving no trace of the secure messages, IBM said. Basic calendar functions, such as accepting and declining meetings, are also provided.
In October, IBM added native iPhone support to its Domino e-mail platform, including push delivery and access to calendars and contact lists.
The IBM announcements are just the latest sign that mobile enterprise applications are beginning to catch on: Last week, HP and Microsoft announced a $250 million effort to build infrastructure for corporate mobility customers.
Google, which recently introduced its Nexus One consumer smartphone has said the next version will be targeted at business customers.