The .NET 3.0 redist package is pretty nice compared to its predecessors in that it is only 2.8MB and will connect to Microsoft via the web to download everything else it needs.

I thought about using it for one of my .NET 2.0 apps, because it would make it 3.0 ready, and also make it easier to distribute.

After some testing though. I found out this information, which may be useful to someone else:

1) .NET 3.0 is just an extension of .NET 2.0 (which is why it works with VS 2005)

2) .NET 3.0 is NOT a full framework. It is a supplement to 2.0. If a system does NOT have .NET 2.0 on it, and you install .NET 3.0, it installs BOTH. you will notice that the .NET 3.0 folder does not contain all the normal framework files, just the things new to 3.0. Everything else is managed by .NET 2.0, including code access security.

3) .NET 3.0 will only run on the following operating systems
Windows XP SP2
Windows 2003 Server SP1
Windows Vista
(Note that on Vista you can NOT install .NET 3.0, it is included out of the box, along with ALL other .NET framework versions to date)

4) So unless you can limit your client base to only having XP SP2, which I know I can't do, you will need to stick with .NET 2.0 which will run on systems as far back as 98 (as long as its all patched up)