If you need to pick the best date for a group of people to meet, WhichDateWorks is a simple service with a polished interface.
WhichDateWorks operates on a simple principle. You create an invitation to an event, enter the email addresses of the people you need feedback from, and send it out. You can limit the range of dates from leaving the entire year open for vote to limiting it selecting from two days. The recipients don't need to sign up to use the service, they simply follow the link that arrives in their email and select the date that works best for them. While WhichDateWorks is fantastic because of its simplicity and polished interface, if you need a service with more detailed time selection you may want to check out When Is Good which lets people select right down to the hour. If you have a preferred service for date selection, share the wealth in the comments below.