$5,700 is the Single Filing Status standard deduction for 2010. What this means is that if you are Single, you do not have to file if you made under 5700 in income. Although you may wish to still file in order to get any refund of income taxes withheld.
In your case, you are married and therefore will likely be filing as married filing jointly. And so you will need to report your wifes income along with yours.
