Zillow has added its new mortgage preapproval tool to the portal's iOS mobile apps for consumers, giving homebuyers the ability to secure a preapproval letter in minutes while they're out house hunting. The preapproval tool, which Zillow launched in March, allows homebuyers to receive a preapproval letter within minutes of sharing their pertinent income, debt and personal info. First it prompts homebuyers to complete a short questionnaire about their income, credit score and monthly debt that gives them an estimated preapproval loan amount. Then, if they’re interested in continuing the process after seeing that estimate, users enter in their name, email address and phone number, which makes their loan inquiry immediately available to lenders in the Zillow Mortgage Marketplace. L...