The Noob's Guide to Open XML Dev (If you know how to spell OpenXML but that's about it, this is your Getting Started guide...)
"This blog post introduces the first in a series of screen-casts that are specifically for a developer starting development with Open XML for the first time. It is a project that I've been meaning to work on for some time, and I recently received the mandate that this should get done, so this is the start of it. In this video, I discuss the Open XML standard from a high level, discuss the resources that helped me get started, and point you to places to find additional resources. I've already recorded the second video, in which I discuss the various tools that you will want to be familiar with in order to do Open XML development. In the third video, I'll discuss the various typical development scenarios for Open XML. In the fourth video, I'll discuss platforms, languages, and libraries, and in the fifth, I'm going to discuss my current thoughts on development approaches. (At least, this is my current plan. We'll see how it proceeds.)
If you are an experienced Open XML developer, this first video in the series is probably not for you. This first video is targeted towards developers who know Open XML is a document format based on XML, and maybe not much more. Experienced developers may get something from subsequent videos, though.
There's some things I love about the OpenXML SDK/format and some I hate (mostly how different the SDK API's are from the Office API's) but the like easily overrides the dis-like. Having an open format that's fully documented and easy(er) to spelunk is a night and day difference over trying to work directly with the Office binary formats.
So if you're a dev and interested in see what this OpenXML SDK thing, need to programmatically read/write OpenXML files (DocX, XlsX, etc) this video and series might be just the thing you need...