Starting up a small business - IT questions?

[El Pago]

I am about to set up a small business with a friend (it will only be the two of us) providing secretarial services to busy families. We are both working from laptops but we don't know how best to set everything up - will we need a server? Or can we simply share documents another way? Any advice/reference books/sites you can give me would be very helpful as I'm a complete novice! Many thanks