Well, I have done it. Now I will try to explain how you can do the same. I remember that I had some problems to implement it myself. Mostly because I was not sure how the whole process works. After some trial and error I figured it out.
I found my first clues on the Eidogo homepage. This information is probably enough if you have a single copy of the board on your personal homepage. This description is not really enough if you want several boards with different games on your blog. At least not to my experience.
So this is how I did...
So go to the Layout section of your blog and click on Edit HTML. Maybe you already have done some of your own cusomizations there. At least I've made a lot of them. Before you start you want to do a backup of your template if you by mistake break anything. Then you can do your changes.
Down there in the later parts of the code you will see a row saying:
Just above this line you add:
Then save the template.
The next step you need to do for every blog post you want to add a weiqi board to. So you start writing a new blog entry. Write any free text and when it is time for your Eidogo board you hit Edit HTML.
Where you want to have your board you enter the text:
The red code in the middle between the div-lines is the content of an sgf-file. Mine here only have four moves. You can use a complete game of course.
Notice that it doesn't work to preview your post...
Now publish your post and you will see something like this!