I have toyed with various products in the past for giving access to files in the office from remote locations (including vpn's, and lots of products call accessmyfiles, or accessmycomputer), but I have to say the simplest and fastest has to be the foldershare site (www.foldershare.com) that Microsoft has just bought. Simple to install and nothing needed on the client apart from a browser, and you are away. What's more performance is good too.
Cheers
Ian