it is good question...
I guess those are technically same.
in my opinion, 'kikitakute' is like she/he want to hear but she/he can't because of some reason. and you can't finish sentences with it or can't make sentences only it. But 'kikitai' is more simple feeling, like she/he just want to hear something. And you can make sentence with only kikitai . or you can finish your sentance with kikitai.
sorry for poor English><
I hope it helps u....