I have found a great silverlight upload control here: http://silverlightuploader.codeplex.com/
If a zip file is selected, I dont know whether it is possible to extract the zip file to check inside the files. if the file is inside OK, the file will be uploaded?
Thanks in advance.
Use SharpZipLib in SL version. You may find this on codeplex: https://slsharpziplib.codeplex.com/
By this lib you can extract files into isolated storage.
Samples: http://wiki.sharpdevelop.net/SharpZipLib-Zip-Samples.ashx#Create_a_Zip_with_full_control_over_contents_0