No need to repeat the good work of others ... Baby Poop 101 has descriptions, pictures, and tons of info.
My interpretation (and 20 year old recollection) of this ... your baby is a bit young to not be pooping with every feeding. Make sure you are feeding for long enough ... don't quit when he fusses .. burp and get back at it. Some mothers are not able to produce enough milk, so you may want to augment with some infant formula before bed and in the morning. It is basically impossible to overfeed at this age.
Along with this ... some advice. Don't over-think or over-analyze. Pay attention to your baby, but don't extrapolate every funny look or squirm into something serious.