I had the 'fun' experience of patching against this vulnerability today. Although, when I rebooted one of my primary servers, it failed to reboot and caused two hours of downtime. Sorry about that to anyone who couldn't access this site.
If you're wondering if you are vulnerable, check your site for Heartbleed vulnerability.
As far as actually patching, I only did it manually on some Ubuntu 12.04 systems. It was fairly simple. Just run
apt-get update && apt-get upgrade
That should take care of it. If you want to learn more, go to Heartbleed.com.
Comic courtesy XKCD: