Whether and how to setup a multi-site Windows 2003 / Small Business Server network over Interent

What are the pro's and con's, gotcha's, land mines, better-do-or-else's of setting up a multi-site Windows 2003 SBS Forest / domain (asusming for the moment this is possible), accessing one another via the Internet?

Background: I have a client running Windows 2003 SBS with 4 local XP clients, attached to Internet via cable broadband connection. They also have 4 remote users running XP and Checkpoint VPN which attach to the domain.local as needed. Client has recently acquired another company running a 3 client peer-to-peer (XP Home) network--not sure of OS of "server" but it is (obviously) not setup as a domain controller...at least the PC's are not members of a "domain". How acquired company connects to Internet, I don't know. But, perhaps this is irrelevent to my question.

More specifically,

0. Is it possible, license-wise, to connect multiple SBS servers in such a way?

1. Technically, broad-brush, what are the major tasks / steps required?

2. Is it advisable to do so? Under what conditions?

3. Does a data center / hosted--including Exchange / Sharepoint--make more financial sense in terms of either one-time setup or ongoing IT support costs, reliability, etc?

3. What type of skills are required to actually do the Windows server / network "setup" work?

4. How much time is required to do this? On-site, remote / Internet?

5. Where can I find these resources in Cincinnati, Cleveland, Pittsburgh?

I'm sure there is more detail you may want or need to know and I will happily provide it. Also, if question is too broad, or depth of answer requires more points, I'll happily create multiple, more specific questions and award points accordingly--for each number in list above and for each "major task."

Thanks in advance,

jack