Yes a VPN is the way. I worked for a Dutch company last year from home. By logging on to the VPN, I had access to all the shared folders, by email, and the company-wide IM system to have instant messages with people I was working with in Amsterdam, other parts of London and New York.

It wasn't technically difficult from my end--but then again the VPN had already been set up at the company before I joined. The firm also set me up with a Blackberry they paid for so I had all my work phone calls in a mobile device as well.

(no longer with them BTW--the company had some financial problems, oh well--back to commuting)