Jan Tielens has done a remake...

After the wonderful Smartpart project (a SharePoint Webpart that can
host any ASP.NET user control), now we have the new Son of Smartpart 1.0, a new
version of the control that will allow you to run
ASP.NET 2.0 user controls and WebParts in the current version of
SharePoint.
From Jan's post:
What is working and what is
not?
Not all features that I would like to be in v1.0 are available
yet, so what is already working and what’s not? The Son of SmartPart (SOSP)
comes in two flavours: one to run ASP.NET 2.0 User Controls (SOSP-UC) and one to
run ASP.NET 2.0 Web Parts (SOSP-WP). For the SOSP-UC version, all the features
from the previous version of the SmartPart are working, so you can expose custom
properties, toolparts, create connectable web parts and so on. The SOSP-WP
version only has the basic functionality to run ASP.NET 2.0 web parts. Advanced
stuff like connections are not yet supported. Support for these advanced
features will follow.
How do you install it?
If you
download the release from the GotDotNet site, you will find an Installation
Guide. I’ve also created a small screencast to guide
you to this process. There is no automated installation yet because the current
version of the deployment tools (STSADM and WPPackager) do not support .NET 2.0
assemblies (yet?).
The project is really cool and recommended for all Sharepoint
developers. Here you
can have a QuickStart tutorial on how to use it.
Thanks Jan! 