Is it possible to auto tweet when I level?

Yes, there’s an extension to TweetCraft that does this called DingTweet that does exactly that, but it needs to be updated to 2.0

Dingtweet has been updated and is currently awaiting approval.

Awesome, let me know when it's up and we'll add a link to the TweetCraft home page :)

Dingtweet update is up.

Just as a note, but links to Dingtweet should go through Curse and not Curseforge :) http://wow.curse.com/downloads/wow-addons/details/dingtweet.aspx