I am looking to design a system where users at 3 remote offices will
need access and in time,
restricted public access via the Internet will be made available. 
It will almost certainly be a web application in Windows ASP or .NET.

What platforms and products are suitable, for building the application?
What features of the products are required to be configured/modified.
What methodologies or best practices exist for guidance in design of
this type of system?
What are the major issues in the design?

How will the three offices actually access the web pages, without going via the
internet. How will web access be made available without comproimising
the networks and other applications. 


Please provide various options for implementations and
advantages/disadvantages as well as  specific features of products
that would be suitable/not suitable.

Also links to case studies of similar systems, and links to postings on
public newsgroups nthat cover both technical and non technical issues.

Please provide as much information as possible to enable me to
research this further. Please answer in the next few days.