Like before, you'll need to create an account and on that account create your characters.  To sign up for raids you'll use the pencil icon next to the raid icon on the calendar.

Raid RSS Feed: http://www.kalicompton.com/raider/index.php?option=com_rss&task=raid

Members DO have the ability to post raids. 

Available

You can sign up as available which basically means "Hey I'm around and can probably raid" (please jot down a note in the comment line)" but won't put you IN the raid. 

Confirmed

Confirmed means that 100% you will be there and you will be placed within the actual raid.

Not Available

This means you can't make it this day what-so-ever.  Handy if you're a tank/healer (I don't care about the army of DPS) where we have so few it's good to know if you can't make raids.