I was actually sent this several months ago and haven't had a chance to write about it. PayScale provides online global compensation info in realtime - which can be handy if you're curious about your industry or if you're thinking of moving to another city (or country) or if you're an employer wanting a salary survey.
For example, below are charts for median salary by years experience for Software Developers and for median salaries across the IT industry. These graphs will update weekly as well. It's pretty versatile - you can narrow the parameters specifically to what you want.