Excellent news for C# developers using Google gData API platform. As of yesterday the gData SVN repository and C# library download have been updated to include C# client libraries for using the new Google Spreadsheets API.
In more good news the C# libraries also fully support development on the Microsoft Mobile platform, so portable apps can make use of online spreadsheet data. Nice one.
I've been looking forward to this since Google announced the spreadsheets API last week. Actually this was something I'd requested from the Writely team before they got bought out by Google. Spreadsheets are a powerful business tool, so I expect to see some good developments in this space.