IBM has become the latest company to release a free suite of office software with hopes of challenging Microsoft’s market dominance in the productivity software market. As of this morning, IBM is offering its IBM Lotus Symphony apps suite for free through its website.

Lotus Symphony is based on open source software from the OpenOffice.org project and comprises word processing, spreadsheet, and presentation applications. As an Open Office derivative, Lotus Symphony employs the Open Document Format to ensure cross-application portability of data. The suite can also import and edit Microsoft Office documents and save them as ODF files.

To date, OpenOffice has failed to put much of a dent in Microsoft's multi-billion dollar office software business. However, OpenOffice isn't the only challenge to Microsoft's dominance in this space. Google also extended its free range of online office tools today by adding a simple presentation tool as a rival to Microsoft PowerPoint. Although Microsoft Office won't lose its dominance in the desktop applications market any time soon, Google seems to enjoy a significant lead when it comes to web-based productivity applications and services, which seems to be where the market is headed.