I am currently using VS 2003 ASP.NET 1.1
I like the way that deployment of a new assembly is so simple, I just
FTP the dll of the entire project across and that's it, none of the
web users are any the wiser. No source code on the server either.

I am thinking of upgrading to VS2005 / asp.net 2.0 but having a quick
and easy way of deploying changes is essential.

My app is a web shop, and there could be several users in the middle
of buying stuff.
If I have a change to make, I want to roll out the changes
instantaniously (eg just replace a dll).

Is this possible with VS 2005 / ASP.NET 2.0 or is it more complicated?

I don't want to knock people off the web sites or give them errors by
doing.

Any help from people with real world experience in this area much
appreciated.