this is how to change ur yahoo account
How To: Set Up Yahoo Mail to work thru GMail
A lot of people have been complaining on not being able to get Yahoo Mail working on their Droid's. So here is a work around for you.
To enable the POP3 access for your free yahoo mail account, all you have to change is the preferred content, setting it to Asia.
Step 1
Select Options->Mail Options, then Account, followed by “Add or edit an account”.
Image 1: Don't be afraid to click the "Add or edit an account" link. It will take you to the old Yahoo Mail interface, but this change is only temporary.
Step 2
Select, the Accounts link on the left of the windows that opens. From the window that opens, select “Account Information” on the left. Then, set: Preferred Content: Yahoo Asia, by clicking on the Edit link, like in this screenshot:
Step 3
Logout and login.
Then, you can enable POP access and change settings, by clicking, from the mail inbox:
Options -> Mail Options -> POP & Forwarding