It was tested with Tornado Smartphone Platform with recent firmware update. It could work with other phones and even with PDAs, hovewer I cant be sure about compatibility, as I had to break some specifications to defuse "anomalies" (bugs?) in the propietary HTC/OMAP USB hardware driver. This just means what it means - some devices have problems with it, and on some WM5torage won't work at all (notably on Typhoon/Feeler/C500/8010/8020 with "unofficial" WM5).
When activated, memory card will not be accessible in the smartphone, as all direct access to the flash card will be routed to USB. Take note that if some currently running programs have files open from the storage card, that can prevent Mass Storage from activation ("error 1f"). In that case, try to close all running programs (soft reset is needed sometimes).
Windows Mobile 5 is required. Sorry, but I cant possibly make it work on WM 2003, as only WM5 allows USB protocol implementation separate from USB hardware driver - on WM 2003 Ill have to rewrite whole USB hardware drivers, and of course its not feasible.
If you want to uninstall it, it is strongly recommended to de-activate mass storage mode first.
Download WM5torage v1.75