I just tried NuGet for the first time tonight, and had a few issues. Not sure if these are NuGet's fault or the package's fault, but I thought I would outline the issue here. Here are the steps to reproduce the problem:
Download ZXing.WP7.v1.0.0 from http://zxingwindowsphone.codeplex.com/SourceControl/list/changesets
Extract zip file and open ZXing.WP7.sln in Visual Studio 2010
The ZXing.WP7.Test project requires a reference to GalaSoft.MvvmLight.Extras.WP7 and GalaSoft.MvvmLight.WP7. If you don't have these installed they will appear as broken references with an exclamation point. In either case, delete these, and try to install this package via NuGet.
Right click on Xing.WP7.Test project and select Add Library Package Reference
Sidenote: I first tried thought NuGet was broken, because I couldn't find any packages. I then figured out that I had to select Online from the side to search for packages from the online repository. I then tried searching for GalaSoft.MvvmLight which did not return any results. That is the namespace and how the broken reference appears in Visual Studio, but the package is named just MvvmLight. Would be nice if the searching user story would address both these issues
Install the MvvmLight package.
Notice that nothing changes in the ZXing.WP7.Test project. Instead a reference to GalaSoft.MvvmLight.Extras.SL4 and GalaSoft.MvvmLight.SL4 is added to the ZXing.WP7 project.
Sidenote: I see that the files get added to a packages folder in the root of the solution. In my opinion this folder should show up as a folder in the solution so that is is visible that files were added. Not a huge deal, but it took me a while to figure out what was going on, especially since the project that I right clicked on was not modified AT ALL! Instead it modified a different project in the solution. Maybe a screen that shows the user what occurred, or a "Click here to view the console results" option that shows what the install did.
At this point a build will still fail, because the library reference was added to the wrong project. Also the wrong reference was added (used SL4 instead of WP7 version. To fix this you have to remove the references from the ZXing.WP7 project and manually add the correct references to the ZXing.WP7.Test. NuGet helps to download the files, but it fails at the installation.
Again, not sure if this is NuGet's fault or the Package creator's fault, but I thought I would post this here as an FYI.
Keep up the great work!