Adapt a differently pin-interspaced chip to be used with an Arduino
Adapters from 2mm to 2.54mm (0.1") spacing exist.

Here is
an example and another example.

Alternatively you could make up a little PCB or, as suggested by @jfpoilpret, solder wires on.

A further option is to cut a piece of stripboard, score down the middle to break the tracks, stick your chip on, and run wires from the 2mm-spaced pins to the 2.54mm-spaced pins.  Off-cut resistor legs work fairly well, in my experience.  Here's one I made (fairly clumsily) earlier.  Your soldering skill may be better than mine. .