Why specifically do you need five colors?
I would definitely recommend looking at the color schemer site. They software is not for free but you can look at a lot of different color combinations that people assembled and use those for free. As far as I remember you can even search by main color.
Personally I got one of those old paper and plastic color wheels you can buy for under $10 at most DIY stores. They have the most common color rules on them.
^ Good suggestion. I might try that out as well since it would be very useful and I don't have to check the web all the time.
Yes use colormatch for instance.