Jbeale shows how to interface the LTC2440 24bit analog to digital converter with the Arduino. He provided the pin connections, a small sketch, as well as some advice to get it up and running.
I should add: to reach the specified noise performance of this part (200 nV RMS) you must have an absolutely clean layout, heavy ground copper and the grounds must be connected in the right way. At first I had > 1 uV RMS, then I removed some bypass caps (dumping current into a sensitive ground area?) and it got quite a bit better to 250 nV but even after some effort, I could not quite reach the spec level with my SSOP->DIP adaptor board. At this level the “excess noise” of resistors (1/f noise) becomes relevant. Physically large metal-film resistors are generally good (low noise). Small cheap SMT resistors are usually noisy.
Via the forum.