Galaxy W Users is having a major improvement! (as i feel), because Arco68 on his "[ROM][JB][JZO54K] CyanogenMod 10 ALPHA (Build 7)" Mod Thread finally enable USB OTG Support on our beloved phone, the Samsung Galaxy W
Thread: http://forum.xda-developers.com/showthread.php?t=1990795
Basically, what does USB OTG do is to make our phone able to connect to external USB devices such as Flashdisk, Card Reader, Keyboard, Mouse, ETC. Myself has tried it with mouse, keyboard and card reader all in single usb HUB and it's works perfectly!
(to make USB Storage such as card reader or flashdisk to be recognized while connecting other devices such as mouse and keyboard, the card reader should be plugged after everything else. This way you can use keyboard and mouse, while working with your flashdisk/hdd/card reader all together)
Using external power source, as our phone doesn't supply power to the Micro USB Port
Mouse confirmed working
Usb Hub Setup
Card Reader Confirmed Working
Usb OTG Converter that i use
Simple usb hub mod for power injection
Very simple schematic
If you have spare time, the setup can even made portable by replacing the usb power adapter with
5V DC Regulator + some battery (9V battery will work i think, the regulator will convert 9V to 5V as required)

Thread: http://forum.xda-developers.com/showthread.php?t=1990795
Basically, what does USB OTG do is to make our phone able to connect to external USB devices such as Flashdisk, Card Reader, Keyboard, Mouse, ETC. Myself has tried it with mouse, keyboard and card reader all in single usb HUB and it's works perfectly!
(to make USB Storage such as card reader or flashdisk to be recognized while connecting other devices such as mouse and keyboard, the card reader should be plugged after everything else. This way you can use keyboard and mouse, while working with your flashdisk/hdd/card reader all together)
Using external power source, as our phone doesn't supply power to the Micro USB Port
Mouse confirmed working
Usb Hub Setup
Card Reader Confirmed Working
Usb OTG Converter that i use
Simple usb hub mod for power injection
Very simple schematic
If you have spare time, the setup can even made portable by replacing the usb power adapter with
5V DC Regulator + some battery (9V battery will work i think, the regulator will convert 9V to 5V as required)