I recently had another project where an eventhandler had to be made. I ended up finding the same articles, that i always find and concluded that it was time to write a quick post with some of the useful links, so I wouldn’t have to search for so long the next time. Hope you may find it helpful as well.
This article (by William Cornwill) is useful to get you started with your first eventhandler.
You may end up having trouble removing your registered events, when using a console application to add then. If so, this little tool could come in handy to get rid of eventhandlers, as well as getting an overview of events across a larger site.
The Event Handler explorer tool
Events can be triggered in many ways and for almost every action you can choose whether the event is being handled synchronous (before the action actually occurs) or asynchronous (after the action occurs). Se a complete list of events here