Unlike iOS, the Windows Phone Marketplace does not have any option to let users switch between Live IDs for particular downloads. The ID you use for setting up your Mango phone remains your primary account, and all Marketplace downloads take place directly through it. The only way to change your primary Live ID is by wiping your phone completely (via a factory reset). This is definitely an extreme measure, but luckily, now you can avoid it (that is, if you have an interop unlocked device). Over at the XDA forum, a new homebrew has been released by the name of IDswitch, which allows users to switch between as many Live IDs as they want! Got an unlocked Windows Phone? Read on to know more.
Using IDswitch can prove to be a bit complicated for some users, and that is why it displays a list of instructions when you launch it for the first time. If you already have a Windows Live ID that is usable on WP7, you don’t have to go through these instructions. If you haven’t got such an ID, create one on your PC and associate it with Zune. Once that has been done, enter the app’s main screen. Here, the app will display your current Live ID, and in the second field, you have to enter the ID you just created and want to use temporarily for app downloads. Tap the switch button at the bottom of the screen, and this will reboot the device.
When the phone is back on, go to the Settings menu, and in the email+accounts section, tap the account name you just added to the phone. Enter that account’s password and let it sync. Now, you have to download the desired apps, but take care to not run these apps for now. After you have downloaded all the apps you want using the new account, go back to IDswitch and revert back to the original ID of your phone, using the same switch button after entering the old ID. Once you do that, you can run the newly downloaded apps, and whenever you want to download more apps using the same new account, do so by switching to it using IDswitch. The best thing about this is the fact that after you have used an ID once with the Homebrew, it will remember it for future use, and you can just tap it from the recently used IDs list. As with most Homebrew apps, IDswitch is available for free, and you can grab it from the source link provided below.