After installing TortoiseSVN 1.6.0, all files loaded into an AnkhSVN enabled Visual Studio 2008 project are marked as new (blue +).
I have tried re-installing AnkhSVN 2.
I can verify that this works, too.
One thing that I ran into was that I uninstalled the older version before installing the new daily build version (I installed AnkhSvn-Daily-2.1.6649.29.msi), but once I installed the new version I didn't have any source code control integration whatsoever in Visual Studio 2008!
As it turned out, when you uninstall AnkhSVN your source code control provider gets set to "None", and you have to go to "Tools | Options | Source Control" and set it back to AnkhSVN.
Once you do that, you're good to go with Visual Studio integration and TortoiseSVN 1.6.