QuickOffice

"Quickoffice Premier for Series 60 is the first mobile office suite to allow you to open, edit & save Microsoft® Word, Excel and PowerPoint® files directly on your Series 60 phone. Quickoffice Premier continues to evolve as the leading mobile office productivity suite and raises the bar in performance functionality.

System Requirements:
Quickoffice Premier v2.0 for Series 60 requires your smartphone to be using Symbian OS version 7 or higher. Some older Series 60 phones will not work with Quickoffice Premier v2.0, though our version 1.0 Quickoffice Viewers will allow you to open attachments for viewing only."

This is a Mobile Office Suite that works with Series60, UIQ and PalmOS.
It's formed of Quicksheet ( Excel-like ), Quickword ( Word-like ) and Quickpoint ( PowerPoint-like ).
It's main drawback is the huge price. This suite costs 49.95$
If you want to try it get it form QuickOffice.com