Best Design for small office network,

I would like to know what is the best way to remotely connect two small office together using the internet. would DSL be ok as a VPN. I have five computers, two at one office and two at the other office,and the server will be at my house and i have cable internet at my home.And i would like to know what O/S should be used i have win. XP Pro. Any info will be helpful. Thanks