>I still want to have my VFP app on each local machine, but now be accessing data centrally via the web instead of the LAN. Can this be done and if so, do I need any third-party add-ons???

One way to do this is via Remote Data Services (RDS). Microsoft KB article Q197861 demonstrates one approach to using RDS. The sample is a set of subclassed VFP controls that simulate "binding" to an RDS data source. Please use the sample only as a guide. It's got some bugs and limitations, and I never got around to fixing it.

Whatever means you choose, it'll take some work. As far as I know, there is no utility that you just drop in and suddenly start pointing to a web server for data. In other words, you can't just say "USE http://www.myserver.com/data/customer.dbf". Certainly stop by http://www.west-wind.com for some other alternatives to reworking your app for use on the web.