With the new Yahoo! Mail interface it might be difficult to find the 'Add an Email Alias' Link. If you go through Mail Options, then select Accounts, you're only presented with an option to link another outside mail account, like a work POP mail account.
But what if you just want another mail account from Yahoo!, like an alias to send spammy things to without having to upgrade to a paid Yahoo! Plus account (with their Disposable Email functionality)?
1. Sign in to your Yahoo! Mail Account
2. Click this link:
http://edit.yahoo.com/config/list_alias
3. Add your new ID which will have an @yahoo.com address
4. Profit.
Note, you only get 1 additional Yahoo! email address to add.
