Hi, meneermalik
I've had a look in Harmony Assistant.
The script you need is to be found in:-
Scripts -> File -> Export -> Batch Export.

(if you don't have this script let me know)

This presents a dialog box where you
1)Select the directory where your ABC files are.
2)Select your Destination Folder mae
3)Change the File Mask to "*.abc"
4)Change the Destination File format to "XML"
5)Click the OK button
and (hopefully) sit back and marvel!
Mike