[nelse]

http://www.worldtimebuddy.com

[fieldforceapp]

http://timeanddate.com is my go-to tool

[binwiederhier]

Use it all the time. Great tool!

[kinlan]

This would be great if it worked on mobile (I.e not desktop optimized)

[kalleboo]

I agree about the lack of mobile web site, but I broke my resistance and the official iOS app is good (there's an Android one too)

[matznerd]

great for coordinating workers and teams in multiple time zones!