Welcome to Justanswer.com, my name is Dustin and I will do my best to assist you.
If you want to use the same exact yahoo messenger id and password ***** your iphone you can.
Simply follow the steps below to download and install yahoo messenger on the iphone, and when its time to sign in use the same id and password ***** use on yahoo messenger on your desktop
If you have further questions or run into any issues, let me know.
I strive to provide great service, and greatly appreciate a rating of excellent ( 5 stars ) selected and submitted below this answer or at the top right of the screen. I always answer follow up questions.Dustin S.Senior Technician and Network Switching Systems Operator / Maintainer.