According to Bruno Terkaly, you have three main choices:
- Traditional Visual Basic for Applications (VBA)
Dates back to all the way to the early nineties.
- Visual Studio Tools for Office.
Really hit its stride and office 2007. It probably represents the best option moving forward today. It tries to be all things to all people.
- The COM Add-In is probably the most powerful, yet the most difficult option of the three.
I’ve borrowed the above words from Bruno. You can read all about those options in his blog post.