Q: MULTIPLE APPLE ID's

Hi I created an Apple ID for my iPod years ago it consited of a username not an email address and covered my iTunes account. I recently bought an iPad and in order to use iCloud had to have an ID with an email address . I duly created a new one which worked (:-)  Unfortunately when I went to the iTunes store and the app store each displayed my old username and demanded it's password; which it then tells me is incorrect!

How do I get Apple to sync my old account so that I am asked for the new email one? I have tried syncing my iPad in iTunes from my PC but this does not change the Apple ID's. Or altenatively does any one know of an Apple web site which will display all my Apple IDs and allow me to edit or delete them? I was give some help recently and a web page to change my ID which worked but I really want to tidy the whole thing up and delete old ID's (hopefully avoiding deleting my iTunes account on my PC! )Yes I know it will be on iCloud but it would be more to do.

Thanks for any advice you can give

Ernie Sweeney