Talk of a tight credit market obscures the fact that mortgages remain available. Here's who qualifies. Homeowners who can't sell may want to rent their homes. But maybe being a landlord isn't all it's cracked up to be. It's called a tax credit, but you have to pay it back over time. Know the rules before you claim this government "gift." A big drop in rates may get many wallflowers onto the refi dance floor. But will falling home values spoil the party?