When you want to download mutations from your banking website, sometimes the only (usable) format of the downloaded file is MT940, as in my case (I have a bank account with the ABN-AMRO bank). I use the term "usable" when talking about wanting to import that file into GnuCash, because the other choice is downloading it in TSV format (Tab Separated Values), which means every freaking time when importing, you have to tell GnuCash what every column is about (or I'm too stupid to work with GnuCash, which I don't rule out entirely).
GnuCash doesn't support MT940 by itself, but you can convert it to OFX format by means of a nice little Java program made by Pieter van Harmelen (on SourceForge at http://sf.net/projects/mtconverter/), but it's a console application and I'm lazy... Thus I wrote a small wrapper in C#, so you can click your way to an OFX file.
It makes the following assumptions:
- Java is installed and java.exe is in your path
- mtconverter.jar is in C:\Windows (yes, hard-coded and with the name "mtconverter.jar")
Furthermore, it needs .NET 4.5 to be installed.
You can find the executable and Visual Studio 2012 C# project on my download page, but here are the direct links too:
Enjoy!