Cut the Rope and Burn the Rope for Android can be downloaded for free from getjar.com, but get them soon. Cut the Rope at least will be free for only a week according to this post. Both games are ad-supported. The ads don’t show up on the game screen in Cut the Rope but do on Burn the Rope.
No direct link to the getjar.com game pages unfortunately as it asks for your mobile phone.
Cut the Rope plays just as well as it’s iOS version though I do wonder how well multi touch actions will work on the smaller screen. (Spoiled by the iPad screen and I have big hands!)