I use Explorations sizer to convert ART designs. It's free, and fairly easy to use.
Link to download below.
My editor by wings is good too, I have played with both True sizer and My editor and I like the True sizer for quick lookie and save, the My editor is better for sizing and changing the design, like removing flowers or leaves, to reduce the size to fit a smaller hoop, I'm still playing with this but I seem to use My editor more than other as of late.
My Editor below
http://www.wingsxp.com/index.php/...
True sizer below
http://www.wilcom.com.au/PRODUCTS...
It's fun to learn new things!
Lucy
Wilcom True Sizer software will open it and then you save it as a pes file format. This is a free software available online, in hopes that you will consider buying the larger program.