Microsoft's Windows Mobile Application Markplace has opened a little wider to encompass any handset running Windows Mobile 6.0 or above. Previously, it was only available to handsets running the very latest version - Windows Mobile 6.5.
The catalogue contains over 800 apps, so it rivals Palm's App Catalog, but both remain a drop in the ocean compared to the Android and iPhone app stores. Still, developers might be more keen to develop for Windows Mobile now that more than a handful of phones can access it.
However, there's always been a vast ecosystem of Windows Mobile applications - they're just not all concentrated in one place. Microsoft now has a hell of a task in front of it, in attempting to collect them together. You can grab it by hitting up mp.windowsphone.com in your phone browser.