While a majority of your users may use the same type of device, there are probably a significant number of users out there who use a different type of device and you should design for multiple platforms. Windows Mobile Pocket PC devices generally have a larger screen than Palm OS devices. A few good rules to keep in mind if you want the same page to look good on both Palm OS and Windows Mobile Pocket PC devices:
If you are trying to center graphics or text, use the <CENTER> tag. Do not pad on white space to your graphics so they look centered on a 150-pixel wide screen. While it might look centered on a Palm, it will look strangely shifted to the left on a Windows Mobile Pocket PC device.
Similarly, do not assume that just because you have an image that is 150 pixels wide, it will take up the full width of the screen.
Be careful about creating graphics that include text. Windows Mobile Pocket PC devices tend to have denser screens than Palm OS devices. The denser the screen is, the smaller the text will appear in a graphic.
Test your site on both a Palm OS and Windows Mobile Pocket PC device.
Your site may have certain pages (like your home page) or graphics (like your logo) that you really want to look absolutely as good as possible on different mobile devices. With a little extra work, it is possible to do this. For instructions, see Using M-Business Client HTTP request headers to customize content and Using server URL macros to customize content.