I've got the Pocketmouse (non Pro edition) and it works great. You may have luck finding it at the Dell store. I ordered it from there (they often have a discount - check techbargains.com) and even though it said not in stock, I specified overnight delivery and it came the next day anyway. (Some times, if you order through the Home Store, they seem to accidentally not charge you for overnight shipping, at least it happened twice to me last month!)
I didn't know about the Pro edition - it sounds handy that the cord retracts into it. The regular one comes with a little carry bag, and it fits nicely into one of the two pockets of my Brenthaven Mobility 1 iBook carrybag.
It also works great with OS X.
Hope that helps.
Jason