Guide to setting up a small office network (~10 users)...

I'd suggest (since you're inexperienced at this) that you keep the email on a web mail server (perhaps provided by your ISP). If you don't REALLY have to set up an Exchange Server (for an internal email server) everything else is easy - just like a large home network.

What have you done so far?

So far what I'm working with is a blank piece of paper and a cheque book. The blank paper is in good supply, however the cheque book has limits!

We are just about to take an office for the first time. Previously we've all worked on laptops on site with the clients we work with. All laptops are XP and even though we are looking to replace some of them, we probably won't go Vista just yet.

Is it as easy as it is at home then? I mean at the moment in my house I have 4 pc's networked together through a router over a wireless network. Can I have one main PC as a server for file and printer sharing etc and to act as the main Internet connection PC?

I'd pick up a 24 port switch just incase you need more. A dumb switch.. You can pick it up at a Best Buy, Circuit City, RadioShack.. Run ya about $120 for a Linksys.

Go with wires, wireless will create minor headaches randomly with people dropping off, slower connections, etc. Buy the cables or see if you can get a local computer shop to custom make the cables. I know store bought cables are extremely expensive unless you go through a distributor like CDW where they cost about 1/10th the store price.

Depending on your ISP/Internet access, you'll probably be fine using a linksys 4 port switch router. Just plug it into your 24 port switch and away you go.
If you get a business class DSL line or Cable, they may even provide you with a business level router which doesn't hurt.