The airdrop is currently ongoing and you can still register.

For everyone who has registered but hasn't received any Piggies yet:

• Please be patient. The airdrop is underway.
• Participants who contribute 0.001 Ether or more receive their airdrop share ahead of others, and they receive the full 168 KiloPiggies early bird share.
  
• At the end of the airdrop (that's a couple of days from now, at the current rate), if you haven't received any airdrop piggies and believe this is in error, you might have gotten caught up in my spam-fighting countermeasures. PM me after the end of the airdrop and we'll see what we can do for you.
  

I'm looking into getting an official listing on EtherDelta, but in the meantime, this link should do the trick.
As for other exchanges, you can help get them interested in Piggies by making this a success on EtherDelta. Obviously Bittrex etc. only want to list tokens that people want to trade