Alejandro,
You can definitely use VFP as a server app for a NET front end, or for any sort of front end. That's pretty much all I do these days.
I'd recommend setting it up as a HTTP server - i.e. a request is sent to your VFP app via http and the response is returned as XML or some other defined format. Check out
http://fox.wikis.com/wc.dll?Wiki~ComparisonOfVFPWebTools~VFP for a few options.
"... They ne'er cared for us
yet: suffer us to famish, and their store-houses
crammed with grain; make edicts for usury, to
support usurers; repeal daily any wholesome act
established against the rich, and provide more
piercing statutes daily, to chain up and restrain
the poor. If the wars eat us not up, they will; and
there's all the love they bear us."
-- Shakespeare: Coriolanus, Act 1, scene 1
