If you've been in business for at least 2 years, a copy of your last 2 years of IRS returns works fine. On the last house I bought, a no doc loan was 1.5% higher. Work that out over the lifetime of your loan and it costs quite a pretty penny to do it that way.
620 is usually the credit score where the mortgage companies are willing to offer you decent terms. 750+ will get their attention even faster.
