Client (exe) calling Business layer (dll) on another machine

[Bob]

I've got a 3-tiered WinForms application in C# .net. The
presentation layer (client exe) contains references to
the Business layer (dll), and everything works great on
the same machine, but when deployed the clients will be
on different machines accessed from the network. How
does the presentation layer call the Business layer from
a different machine?

I know I can use WebServices, but that doesn't seem right
for an business application within a network with only a
hand full of users.

Is Remoting my only other solution that makes sense? Is
there another alternative.

No distributed transactions by the way. (no COM+,
hopefully)

Any help would be great,
Bob