Advice on VB application Architecture

[CodeMonkey]

Hi,

I was wondering if anybody could give me some advice on how to
structure an application that I am about to start work on.

The vague requirements will be:
1) Always-On monitoring of data (e.g. through serial port and other
sources)
2) Local machine user interface
3) Remote machine user interface (networked)

Future expansion may include:
4) Web interface
5) Mobile device interface

OS that it has to run on: Windows NT/2000/XP, (Windows 98SE/ME -
without web/mobile)

So far here's the architecture that I've come up with (All to be
developed with VB.net)

Windows Service app to:
-- Host Class Library (to implement core functionality - DB, comms
etc.)
-- Host Plug-ins (for future expansion)
-- Allow core system to run even when no user logged on

Windows Forms Application to communicate with service through remoting
(on local machine and remote machine)

ASP.Net Application to communicate with service in the same manner as
the Windows forms User interface (Future)

Mobile Application to communicate with service in the same manner as
the Windows forms User interface (Future)
Here's a few questions that I have:
1) Is there any major hassles with an application communicating with a
windows service through remoting? (Apart from performance)

2) Will a windows service application run on Windows 98 (possibly
through the "RunServices" registry key)?

3) Is there any major issues with remoting on Windows 98?

Thanks in advance for your help and advice,

Trev.