Sure!
Frevo is strictly música nordestina. In Recife, where frevo originates, it's mostly connected with Carnaval in the same way that Samba is in Rio or São Paulo. It's upbeat and kind of playful. Here's a YouTube link I like:
http://youtu.be/Ydr848aAqz4
Axé is quite different. To me, it has a much more tropical kind of sound. Lot's of percussion, typically from wood instruments, and singing. YouTube doesn't have as many Axé videos as it does Samba and Frevo and many of the Axé you'll see there are from Spanish cultures that have adapted Axé in their own way. In my opinion, Axé from Brazil is the best though, especially Axé from Bahia.
What música brasileira do you like?