With the shock of hearing about a potentially profitable Twitter side project only just abating now, six months on, we can fill in a few details about the almost-secret iPhone/credit card scheme from the company's Jack Dorsey.

According to reports of a few trials around New York, the project is to be called either Square or Squirrel – we're guessing the latter just because it seems to go well with the name Twitter.

Good to go

As we already knew, it will involve a physical adapter that attaches to an iPhone to make it into a mobile credit-card-reading terminal. The idea is to allow small businesses or even individuals to process cards just like larger retailers can.

Tech website Engadget also has screenshots of the associated app in action, showing the domain paybysquirrel.com in the receipt displayed on an iPhone. PayPal watch out.