Okay, its probably not really that easy.  But I hate with the passion of a thousand suns the whole appointment dance. You know.

"When's good for you?"

"Oh, anytime."

"Next Tuesday, 3pm?"

"Except then."

and it goes on and on.

TimeDriver lets you set what days and times you're available, you can send clients to your online calendar, they can pick what works for them, then TimeDriver will synch with Google Calendar or Outlook.  You can even put a "schedule now" button in your emails.  Looks interesting.

Cost - Free

Platform - webbased, shouldn't matter