As convenient as it is to call the ATIS telephone numbers, it's also important to keep in mind that this is a vital resource for pilots and aviation professionals. As an enthusiast, calling will tie up the line which in turn may prevent a more official use (ie, busy signal for a pilot, dispatcher, etc). I, in addition to many of the pilots at the company I work for also use the numbers to get important airport and weather information that isn't updated as quickly on the internet.
There is nothing more frustrating than a busy signal. Especially in 2009.