I wrote favorably about the idea of TimeBridge last year. It's a service that's supposed to make scheduling meetings less of pain in the neck, by letting an organizer send out several proposed times for a meeting, and then coordinating the replies of attendees until everyone agrees on a single time, at which point it will lock in the agreed-on time for everyone and release the tentative hold it had on the alternate spots.
The service is now in public beta (finally), and I've been using it to schedule meetings. The upshot: It works great.
What I like best about TimeBridge is its integration with Outlook. There's a very handy "Reply with TimeBridge" option that it adds to Outlook if you install the add-on. If someone sends you an e-mail about a meeting, you can use this option to transfer the discussion over to the TimeBridge system. Your recipient will get a link to a Web page, where it's easy to select one of the meeting times you propose. Or, if you instead start a conversation about a new meeting, TimeBridge reads your recently-used Outlook e-mail recipients to make entering in the recipient very easy. In ether case, TimeBridge syncs with your Outlook calendar and shows you the times you have available, which makes picking possible meetings slots easy.
If there are people you meet with frequently, you can share your general availability with them, allowing them to propose meeting times when you're available. The system only shows when you have appointments booked, not with whom or where they are.
My small beefs with TimeBridge are these: First, from within Outlook it pops up Internet Explorer screens for its functions, even if your default browser is set to Firefox. Second, it doesn't let you assign more than one tentative meeting spot to a time block during the negotiation phase. This keeps things simple, but there are some meetings for which users might feel a musical chairs approach to scheduling would work. I'd like the option, at least.
TimeBridge will always be a free version, CEO Yori Nelken told me. Premium versions will be available with more features. Competitive service iPolipo (review), in contrast, has only a 30-day free trial, and it requires you to give up either a PayPal authorization or a credit card number to access it. That's cracked. Try TimeBridge.