Practically the entire business world uses Microsoft Office in some capacity or another. Though today's smart devices are easily powerful enough to do the same, at least with reasonably sized files, editing documents on smartphones is not as ubiquitous as it should be. That's because though many Windows Mobile Pocket PC phones come with the ability to modify and save documents, less-capable Windows Mobile smartphones still lack that functionality. And phones running other operating systems such as the Palm OS, Symbian, or BlackBerry OS need separate solutions to do this. DataViz's Documents To Go suite has been a perennial favorite in this space, and my testing proves it's still the leader in document editing on Palm-based handhelds.

In fact, a version of the software often comes installed on many Palm OS smartphones right from the factory. With this in mind, I tested the latest, version 9, which finally allows you to preserve tracked changes and other complex formatting features when editing and resaving documents. DataViz's proprietary Intact Technology lets you open documents in their native format, edit them, resave them, and then forward them to other users. This ability is vital when collaborating with other people in a business environment. Quickoffice Premier also offers this functionality, though as we'll see, Documents To Go exceeds Quickoffice, particularly in its ability to edit PowerPoint files.

I tested the Palm OS version of Documents To Go 9 Professional ($39.95 direct) on a Sprint Palm Treo 700p, though versions also exist for Symbian Series 80 (the Nokia 9300 and 9500) and Symbian UIQ-equipped smartphones.

Right from the get-go, it's clear that the 700p and Documents To Go are a powerful combination. The 700p's excellent 320- by 320-pixel screen resolution gives you a lot of room to work with for such a tiny device, and its built-in touch screen and stylus make quick work of navigating around a document, even when compared with using a mouse on a regular PC. DataViz also provides an icon toolbar at the bottom of the screen that gives you quick access to common tasks, depending on which module you're using.

I'll step through each of the four main modules and go over what's significant in each one. Word To Go's comprehensive functionality, plus its ability to handle complex formatting easily, makes it a powerful portable word processor. I had no problem opening documents, making changes, and resaving them. And I could view them back on my main PC without any problem. In my opinion, this is more typical of the kind of use you'd expect to get out of Documents To Go. As I noted in the Quickoffice review, I don't expect most users to create large documents from scratch using a smartphone's tiny keyboard. But significant revisions and other editing shouldn't be much of a problem.

DataViz's portable Excel replacement, Sheet To Go, juggles dozens of formulas and different kinds of formatting with aplomb. I was disappointed to see that you couldn't undo certain changes, such as inserting rows and columns, but the sheer breadth of function and sorting support is breathtaking in a mobile application. Documents To Go's speed is also impressive; I was able to navigate a fairly large spreadsheet without any appreciable slowdown.

Slideshow To Go can present your slides in outline format for a quick overview. Interestingly, there's significantly more functionality here than there is in Quickoffice Premier's Presentation module. Unlike that application, Slideshow To Go lets you cut and paste text, sort slides, indent text, and more. It's still no desktop PowerPoint equivalent, but if you're planning on doing heavy presentation file work, Documents To Go is a better choice than Quickoffice.

Even the software's PDF To Go module is slick; you can drag the view your way around documents using the stylus. First, set the zoom level to 100 percent, and then use the stylus to move the entire document around. This way, you actually have a shot at reading the text without causing eye strain. Again, the Palm OS's high screen resolution comes into play here, but there's no denying that DataViz's tightly written code contributes to the sheer speed of the viewer. In fact, it feels about as fast as viewing PDFs on a Windows XP machine, though I did have to wait several seconds for each PDF to load.

DataViz sells several versions of Documents To Go. The Standard version ($29.95) includes the basic word processor and spreadsheet, but leaves out the presentation module and PDF viewer. The Professional version ($39.95) adds those two features. For another 10 bucks, the Premium edition ($49.95) gives you a spell-checker, file explorer, the ability to password-protect files, and the ability to use charts and pictures. These features really should be included; in fact, I recommend skipping Professional and purchasing the Premium edition instead. Finally, the Total Office suite ($89.95) adds Microsoft Outlook and Access compatibility.

Regardless of the version, Documents To Go 9 is a killer document editing suite. It's a must-purchase for just about anyone with a Palm OS–based Treo who wants to work with Microsoft Office files on the go.