SpreadsheetLight
Simple and intuitive, SpreadsheetLight is a .NET-compatible software library you can use to create and modify (Excel) spreadsheets. With comprehensive styling functions, fast cell data processing time and the shallowest learning curve you will probably see, SpreadsheetLight is an ideal spreadsheet automation tool. Find out more here.
Spreadsheet Open XML From Scratch
Need to create Microsoft Excel spreadsheets using C#/VB.NET and Open XML SDK? Get this guide now. Armed with full working source code, in-depth explanation of Open XML concepts and a 140+ page PDF filled with programming goodness, you never have to fear another spreadsheet. Ever. More information here.
Code Help Session
Byte-sized fixes for your code. Minimum fuss. Get help here.